fix: the swap decoder names where a WRAP_ETH pays and shows a V4 step's ETH as a maximum when the router may hold ETH (closes #665)

A `WRAP_ETH` that sets the input side and pays its WETH to anyone but
the router names that recipient on its `Moved to` line.

V4 pays a `SETTLE` of ETH from the router's own ETH, whichever payer it
names. When an earlier step may leave ETH in the router, the ETH that
the user pays a later V4 step gets lines of its own. Their
`Moved from the sender` line reads `Up to <amount>`, or
`Unknown (could not be decoded)` when the amount is not known. The
decoder never subtracts the router's ETH, so no line shows less ETH
than can leave the wallet. Without such an earlier step, the lines read
as before.

Model: opus-5-5

docs/README.md

@@ -57,11 +57,12 @@ analytics, use a portfolio tracker. The wallet is not the place for any of that.
 
 - **No NFT galleries or portfolio views.** This is a wallet, not a dashboard.
 
-- **No third-party token list APIs.** Token balances come from the same block
+- **No third-party token list APIs.** The balances of the tokens you track are
-  explorer you configure for transaction history, and the extension ships its
+  read from your RPC endpoint. While "Use Blockscout" is on, the other tokens
-  own hardcoded list of top ERC-20 contract addresses for symbol-spoofing
+  come from the same block explorer you configure for transaction history. The
-  detection. Any token you want tracked across all your addresses, you add
+  extension ships its own hardcoded list of top ERC-20 contract addresses for
-  yourself by contract address.
+  symbol-spoofing detection. Any token you want tracked across all your
+  addresses, you add yourself by contract address.
 
 - **No backend servers operated by the developer.** Nothing is sent to any
   server run by AutistMask. Every network destination is listed below.
@@ -69,8 +70,13 @@ analytics, use a portfolio tracker. The wallet is not the place for any of that.
 ## How It Works
 
 AutistMask is a browser extension that runs entirely in your browser. It does
-not have a backend server. It communicates with five external destinations:
+not have a backend server. Out of the box it sends your data only to the
-three you configure yourself, and two fixed ones used for scam detection.
+Ethereum RPC endpoint. It also asks the CoinDesk price API for prices, sending
+token symbols and nothing else.
+
+Blockscout and Etherscan are sent none of your data until you turn on a setting
+for each. The settings are "Use Blockscout" and "Check recipients on Etherscan".
+Both are off in a new install. Welcome and Settings both offer them.
 
 ### External Services
 
@@ -83,11 +89,14 @@ verify confirmations. The default is a free public RPC endpoint. You can change
 this in Settings to any Ethereum JSON-RPC endpoint, including your own local
 node.
 
-When it is contacted: on every balance refresh (every 10 seconds while the popup
+When it is contacted:
-is open, every 60 seconds in the background), when you type an ENS name into the
+
-Send screen, when a send is prepared and broadcast, while a pending transaction
+- on every balance refresh (every 10 seconds while the popup is open, every 60
-is polled for its receipt, and for the reverse ENS lookups used to label
+  seconds in the background)
-addresses (cached for 12 hours).
+- when you review a send to an ENS name
+- when a send is prepared and broadcast
+- while a pending transaction is polled for its receipt
+- for the reverse ENS lookups used to label addresses (cached for 12 hours)
 
 What gets sent: standard Ethereum JSON-RPC requests (balance queries,
 transaction broadcasts, gas estimates, ENS lookups, contract-code checks). Your
@@ -96,16 +105,31 @@ addresses are necessarily visible to the RPC provider when querying balances.
 **Blockscout API** (default: `eth.blockscout.com/api/v2`;
 `eth-sepolia.blockscout.com/api/v2` on Sepolia)
 
-Used to fetch token balances and transaction history. Blockscout is an
+Blockscout is an open-source blockchain explorer. AutistMask sends it your data
-open-source blockchain explorer. AutistMask queries it for your ERC-20 token
+only while "Use Blockscout" is on. AutistMask then asks Blockscout for:
-balances (including the holder counts used for spam filtering) and your recent
-transactions and token transfers. You can change this in Settings to a
-self-hosted Blockscout instance.
 
-When it is contacted: on every balance refresh, and whenever a screen showing
+- your recent transactions and token transfers
-transaction history is opened.
+- the balances of the tokens you have not tracked, with the holder counts used
+  for spam filtering
+- the block, fees and calldata of a transaction you open
 
-What gets sent: your Ethereum addresses (to look up balances and transactions).
+You can change the endpoint in Settings to a self-hosted Blockscout instance.
+While the setting is off, each screen that would show Blockscout's data says
+instead that the setting is off. Only the tokens you track are listed. When you
+turn the setting off, every other token leaves the lists at once.
+
+When it is contacted, while "Use Blockscout" is on:
+
+- on every balance refresh
+- whenever a screen showing transaction history is opened
+- when you open a transaction
+
+Pressing "Save" beside the Blockscout URL in Settings checks the URL by asking
+it for `/stats`. That happens whether or not the setting is on. The request
+sends none of your data.
+
+What gets sent: your Ethereum addresses (to look up balances and transactions)
+and the hash of each transaction you open.
 
 **CoinDesk CADLI price API** (`data-api.coindesk.com`)
 
@@ -122,16 +146,21 @@ address.
 
 **Etherscan address labels** (`etherscan.io`; `sepolia.etherscan.io` on Sepolia)
 
-When you review a send, AutistMask fetches the recipient's public Etherscan
+While "Check recipients on Etherscan" is on, AutistMask fetches the recipient's
-address page and looks for a "Fake_Phishing"/"Phish/Hack" label or a scam
+public Etherscan address page when you review a send. AutistMask looks for a
-warning, and shows a red warning if it finds one. This is a plain page fetch
+"Fake_Phishing"/"Phish/Hack" label or a scam warning, and shows a red warning if
-with no API key, made by your browser. It is best-effort: if it fails, it is
+it finds one. This is a plain page fetch with no API key, made by your browser.
-silently ignored. This endpoint is not user-configurable.
+It is best-effort: if it fails, it is silently ignored. This endpoint is not
+user-configurable.
 
-When it is contacted: each time you reach the send confirmation screen.
+The setting is off in a new install. While it is off, the confirmation screen
+says that no Etherscan check was made.
 
-What gets sent: the recipient address you are about to send to, and your IP
+When it is contacted: only while "Check recipients on Etherscan" is on, each
-address. Your own addresses are not sent.
+time you reach the send confirmation screen.
+
+What gets sent: the recipient's address and nothing else. As with any request,
+Etherscan sees your IP address.
 
 Etherscan links shown elsewhere in the UI (on addresses, transactions, and token
 contracts) are ordinary links. They contact nothing until you click them.
@@ -179,12 +208,18 @@ password.
 3. Click "Load Temporary Add-on".
 4. Select `dist/firefox/manifest.json`.
 
+AutistMask does not work in Firefox private windows. If Firefox is set to "Never
+remember history", every window is private, so AutistMask does not work at all.
+
 ## Getting Started
 
 ### Creating a New Wallet
 
 1. Click the AutistMask icon in your browser toolbar.
 2. Click "Add wallet" (on first use), or open Settings and click "+ Add wallet".
+   On first use, the screen with "Add wallet" also offers "Use Blockscout" and
+   "Check recipients on Etherscan", both off. External Services above says what
+   each one does. You can change both later in Settings.
 3. On the "From Phrase" tab, click the die button to generate a random 12-word
    recovery phrase.
 4. **Write down the recovery phrase and store it safely.** Anyone with these
@@ -220,10 +255,14 @@ always produce the same sequence of addresses.
 
 ### Adding ERC-20 Tokens
 
-Tokens you hold show up automatically only if they are in the extension's
+The wallet looks for tokens you hold only while "Use Blockscout" is on. Even
-bundled list of well-known tokens or have at least 1,000 holders; everything
+then, a token shows up only if it is in the extension's bundled list of
-else is treated as spam and hidden. To track a token explicitly (which also
+well-known tokens or has at least 1,000 holders. Everything else is treated as
-shows it at zero balance), add it by contract address:
+spam and hidden.
+
+The wallet shows every token you track, whether or not "Use Blockscout" is on.
+By default a tracked token is shown at zero balance too (see Display in
+Settings). To track a token, add it by contract address:
 
 1. Go to an address detail view (click `[info]` on any address).
 2. Click "+ Token".
@@ -237,9 +276,12 @@ screen. Tokens can also be added from Settings, under "Tracked Tokens".
 ## Sending
 
 1. Click "Send" from the home screen or an address detail view.
-2. Select what to send (ETH, or any ERC-20 token with a balance on this address
+2. Select what to send: ETH, or a token you track that this address holds. While
-   that survives the spam filters).
+   "Use Blockscout" is on, Send also offers other tokens with a balance on this
-3. Enter the recipient address or ENS name (e.g. `vitalik.eth`).
+   address that survive the spam filters.
+3. Enter the recipient address or ENS name (e.g. `vitalik.eth`). AutistMask does
+   not look up a name resolved off-chain. For such a name, enter the address
+   instead.
 4. Enter the amount, or click "Max" to fill it in: a token's balance, cut to 18
    decimal places, or your ETH balance minus the amount reserved for the network
    fee.
@@ -256,9 +298,13 @@ The confirmation screen shows:
   estimate, and below it the larger amount reserved until it confirms. The
   reserve is what the network requires up front and what the balance check gates
   on; the refund of the difference is why the two differ
-- **Warnings** if the recipient is a contract, a burn address, one of your own
+- **Warnings** if the recipient is:
-  addresses, on the bundled scam-address list, or labelled as a phisher on
+    - a contract
-  Etherscan
+    - a burn address
+    - one of your own addresses
+    - on the bundled scam-address list
+    - while "Check recipients on Etherscan" is on, labelled as a phisher on
+      Etherscan
 
 After reviewing, enter your password and click "Sign & Send". The transaction
 will be broadcast to the network and you will see a waiting screen with a timer.
@@ -269,8 +315,9 @@ screen with the transaction hash and an Etherscan link.
 
 You can also send from a token-specific view: on the address detail screen,
 click any token balance row. This opens a focused view showing only that token's
-transactions. Clicking "Send" from here pre-selects and locks the token so you
+transactions. While "Use Blockscout" is off, the view says instead that no
-cannot accidentally switch to a different one.
+transaction history is shown. Clicking "Send" from here pre-selects and locks
+the token so you cannot accidentally switch to a different one.
 
 ## Receiving
 
@@ -306,6 +353,13 @@ enter your password and click "Confirm" to authorize it. Message and typed-data
 signature requests work the same way, with a "Sign" button, and also require
 your password.
 
+If a transaction or signature popup closes before you answer, for example when
+you click away to copy your password, the request stays open. Closing the popup
+does not turn the request down. Click the AutistMask icon in your browser
+toolbar to bring the request back. Until you answer, the icon opens the request
+instead of your wallet. If several requests are waiting this way, the oldest
+comes first.
+
 A connected site can also ask to switch the wallet's network. A popup shows the
 site's origin, the current network and the requested network. Nothing changes
 unless you click "Switch"; clicking "Reject" or closing the popup leaves
@@ -344,11 +398,12 @@ balances unless they are on the bundled known-token list or you added them
 yourself. Legitimate tokens have substantial holder counts; scam tokens deployed
 for address poisoning typically have zero. When the explorer reports no holder
 count for a token, or reports something other than a whole number in plain
-digits (such as "1,000"), the count is unknown. An unknown count does not hide a
+digits (such as "1,000"), the count is unknown. While "Use Blockscout" is off,
-token from your transaction history or the send token list, and it does not get
+no holder count is known. An unknown count does not hide a token from your
-a token into your balances either: such a token is listed only if it is on the
+transaction history or the send token list, and it does not get a token into
-bundled known-token list or you added it yourself. The screen you reach by
+your balances either: such a token is listed only if it is on the bundled
-clicking a token balance shows a "Holders:" line only when the count is known.
+known-token list or you added it yourself. The screen you reach by clicking a
+token balance shows a "Holders:" line only when the count is known.
 
 **Fraud contract blocklist.** When AutistMask detects a fraudulent transfer, it
 adds the contract address to a local blocklist. Future transactions from that
@@ -380,6 +435,8 @@ see everything unfiltered.
 Click the gear icon on the home screen to access settings:
 
 - **Wallets**: Your wallets, and "+ Add wallet".
+- **Passwords**: Tick "Allow weak passwords" to choose a password shorter than
+  12 characters when you add a wallet.
 - **Tracked Tokens**: The ERC-20 tokens tracked across all addresses, and "+ Add
   token".
 - **Display**: Toggle whether tracked tokens with zero balance are shown, switch
@@ -389,8 +446,9 @@ Click the gear icon on the home screen to access settings:
   that network's defaults if you have not used it before.
 - **Ethereum RPC**: Change the Ethereum node endpoint. Default is a public RPC.
   You can use your own node for maximum privacy.
-- **Blockscout API**: Change the Blockscout instance used for token balances and
+- **Blockscout API**: the "Use Blockscout" checkbox, off until you tick it, and
-  transaction history. You can use a self-hosted instance.
+  the URL of the Blockscout instance. You can use a self-hosted instance.
+- **Etherscan**: "Check recipients on Etherscan", off until you tick it.
 - **Token Spam Protection**: Toggle individual scam filters and set the dust
   transaction threshold.
 - **Allowed Sites / Denied Sites**: View and manage web3 site permissions.

manifest/firefox.json

@@ -4,6 +4,7 @@
     "version": "0.1.0",
     "description": "Minimal Ethereum wallet for Firefox",
     "permissions": ["storage", "activeTab", "alarms", "<all_urls>"],
+    "incognito": "not_allowed",
     "content_security_policy": "default-src 'self'; script-src 'self' 'wasm-unsafe-eval'; object-src 'self'; style-src 'self'; img-src 'self' data:; connect-src 'self' https: http:; frame-src 'none'; form-action 'none'; base-uri 'none'",
     "icons": {
         "16": "icons/icon16.png",

src/background/index.js

@@ -17,7 +17,11 @@ const { applyChainSwitchFields } = require("../shared/chainSwitchFields");
 // the same prohibition reported early, not the guarantee.
 const { getState, updateState } = require("./state");
 const { StateUnusableError } = require("../shared/stateSchema");
-const { refreshBalances, getProvider } = require("../shared/balances");
+const {
+    refreshBalances,
+    dropUntrackedTokens,
+    getProvider,
+} = require("../shared/balances");
 const { debugFetch, log } = require("../shared/log");
 const {
     verifySignedTx,
@@ -157,9 +161,9 @@ let txApprovalSlot = null;
 const APPROVAL_PENDING_CODE = -32002;
 
 // True at every moment this can be sent: the slot is taken immediately before
-// the transaction is populated, so the other request is either being prepared
+// the transaction is populated, so the other request is being prepared, is on
-// or on screen. It does not claim the other one is displayed yet, because for
+// screen, or waits with its window closed. It does not claim the other one is
-// the length of one network round trip it is not.
+// displayed yet, because for the length of one network round trip it is not.
 const TX_APPROVAL_PENDING_MESSAGE =
     "AutistMask handles one transaction at a time, and another one is" +
     " already in progress, so this one was not sent. Please finish that" +
@@ -379,14 +383,26 @@ async function proxyRpc(method, params) {
     return json.result;
 }
 
-// The site-connection approval the toolbar popup is set to open, or null while
+// The approval the toolbar popup is set to open, or null while it opens the
-// it opens the wallet. Set only by resetPopupUrl() and showInToolbarPopup().
+// wallet. Set only by updateToolbarPopup() and showInToolbarPopup().
 let toolbarPopupApprovalId = null;
 
-function resetPopupUrl() {
+// Point the toolbar popup at the oldest pending approval whose window closed,
-    toolbarPopupApprovalId = null;
+// or at the wallet when there is none. The user can then answer that approval
+// from the toolbar popup. pendingApprovals lists approvals in the order they
+// were added, so the first one found is the oldest. An approval held by a
+// running attempt is skipped until that attempt ends.
+function updateToolbarPopup() {
+    const closed = Object.values(pendingApprovals).find(
+        (approval) => approval.windowClosed && !approval.attemptInFlight,
+    );
+    toolbarPopupApprovalId = closed ? closed.id : null;
     if (actionNs && typeof actionNs.setPopup === "function") {
-        actionNs.setPopup({ popup: "src/popup/index.html" });
+        actionNs.setPopup({
+            popup: closed
+                ? "src/popup/index.html?approval=" + closed.id
+                : "src/popup/index.html",
+        });
     }
 }
 
@@ -416,15 +432,16 @@ function settleApproval(id, result, options) {
     // approval stops being alive.
     releaseTxApprovalSlotFor(id);
     approval.resolve(result);
-    resetPopupUrl();
+    updateToolbarPopup();
     return true;
 }
 
 // What a pending approval resolves to when it is given up on rather than
-// answered: the window was closed, or could not be opened at all. A tx or sign
+// answered: a site-connection or network-switch window was closed, or the
-// approval answers the requesting page in EIP-1193 shape; a site-connection or
+// window could not be opened at all. An address switch in the wallet gives up
-// network-switch approval answers its handler in the shape the popup's
+// pending approvals too. A tx or sign approval answers the requesting page in
-// decision has, as a refusal.
+// EIP-1193 shape; a site-connection or network-switch approval answers its
+// handler in the shape the popup's decision has, as a refusal.
 function abandonedResult(approval, code, message) {
     if (approval.type === "tx" || approval.type === "sign") {
         return { error: { code, message } };
@@ -432,8 +449,9 @@ function abandonedResult(approval, code, message) {
     return { approved: false, remember: false };
 }
 
-// A window the user closed without answering is a refusal by the user, which
+// A site-connection or network-switch window the user closed without answering
-// is 4001 and the wording every other rejection path already uses.
+// is a refusal by the user, which is 4001 and the wording every other rejection
+// path already uses.
 const APPROVAL_REJECTED_CODE = 4001;
 const APPROVAL_REJECTED_MESSAGE = "User rejected the request.";
 
@@ -461,31 +479,16 @@ const APPROVAL_WINDOW_FAILED_MESSAGE =
 function claimApproval(approval) {
     if (approval.attemptInFlight) return false;
     approval.attemptInFlight = true;
+    updateToolbarPopup();
     return true;
 }
 
 // Release an approval whose attempt failed in a way the user can retry.
-// Nothing was broadcast, so the next attempt may claim it.
+// Nothing was broadcast, so the next attempt may claim it. If the user closed
-//
+// its window while the attempt ran, the toolbar popup opens it for that retry.
-// Unless the window it would be retried in is already gone. The user closed it
-// while the attempt was running and settleApproval() declined then, correctly,
-// because the attempt still owned the approval; the attempt has now failed, so
-// nothing owns it and nothing can reach it. Left standing it would hold the
-// requesting page's promise open forever and, with it, the transaction
-// approval slot. It is settled here as the rejection the closed window
-// already meant.
 function releaseApproval(approval) {
     approval.attemptInFlight = false;
-    if (approval.windowClosed) {
+    updateToolbarPopup();
-        settleApproval(
-            approval.id,
-            abandonedResult(
-                approval,
-                APPROVAL_REJECTED_CODE,
-                APPROVAL_REJECTED_MESSAGE,
-            ),
-        );
-    }
 }
 
 // Open approval in a separate popup window, unless it is no longer pending.
@@ -708,9 +711,7 @@ function isExtensionSender(sender) {
 // had refused.
 //
 // TX and sign approvals do not decide here. They stay pending across a
-// disconnect. When their window closes, the windows.onRemoved listener below
+// disconnect, and across their window closing, until the user answers them.
-// rejects them, unless an approved attempt is still running, in which case
-// that attempt answers the page.
 runtime.onConnect.addListener((port) => {
     if (port.name.startsWith("approval:")) {
         const id = port.name.split(":")[1];
@@ -738,9 +739,7 @@ runtime.onConnect.addListener((port) => {
             const approval = pendingApprovals[id];
             if (approval) {
                 if (approval.type === "tx" || approval.type === "sign") {
-                    // When its window closes, windows.onRemoved rejects it,
+                    // It stays pending until the user answers it.
-                    // unless an approved attempt is still running, in which
-                    // case that attempt answers the page.
                     return;
                 }
                 settleApproval(id, { approved: false, remember: false });
@@ -1293,7 +1292,7 @@ async function broadcastAccountsChanged() {
             windowsRemove(approval.windowId).catch(() => {});
         }
     }
-    resetPopupUrl();
+    updateToolbarPopup();
     // An address switch ends every connection allowed without "Remember". This
     // waits on storage, so it comes after the pending approvals above, which
     // are still rejected the moment the switch arrives.
@@ -1386,6 +1385,10 @@ const RECENT_BALANCE_REFRESH_MS = Math.floor(BALANCE_REFRESH_PERIOD_MS / 2);
 // back over them (https://git.eeqj.de/sneak/AutistMask/issues/577).
 // lastBalanceRefresh is left as the switch set it, so the next tick refreshes
 // the new network.
+//
+// Blockscout may have answered just before the user turned "Use Blockscout"
+// off. So the save reads the stored setting again, and drops every token the
+// user has not tracked if the setting is off.
 async function backgroundRefresh() {
     const s = await getState();
     const now = Date.now();
@@ -1423,6 +1426,9 @@ async function backgroundRefresh() {
                 }
             }
         }
+        if (!fresh.useBlockscout) {
+            dropUntrackedTokens(fresh.wallets, fresh.trackedTokens);
+        }
         fresh.lastBalanceRefresh = now;
     });
 }
@@ -1478,36 +1484,44 @@ if (runtime.onStartup) {
 }
 startBackgroundJobs();
 
-// When approval window is closed without a response, treat as rejection.
+// The toolbar popup keeps its URL when the worker stops. A worker that starts
-// "Without a response" is the operative part: the popup stays open across the
+// holds no approvals, so the toolbar popup is pointed back at the wallet.
-// verify and broadcast it is waiting on, so a user closing an apparently-hung
+updateToolbarPopup();
-// window is an ordinary event with an attempt already in flight behind it.
+
-// settleApproval() refuses those, which leaves the attempt to report its real
+// A transaction or signature approval stays pending when its window closes.
-// outcome to the page — and the window is recorded as gone, so that an attempt
+// The browser can close that window when the user clicks away from it, for
-// which then fails retryably settles instead of waiting in a window that no
+// example to copy the password from a password manager. The approval is marked
-// longer exists.
+// as closed, so the toolbar popup can open it (see updateToolbarPopup()). An
+// attempt already running when the window closes goes on and reports its
+// outcome to the page.
 //
-// A site-connection or network-switch approval whose popup connected its port
+// This listener rejects a site-connection or network-switch approval whose
-// is not decided here. That popup approves and closes in the same breath, and
+// window closes before its popup connected its port. Once the port is
-// this event races the decision on a channel of its own — the same race the
+// connected, the approval is left to the port. That popup approves and closes
-// port exists to end. Its port disconnect says the same thing this event does,
+// in the same breath, and this event races the decision on a channel of its
-// in an order that is defined, so the disconnect is left to say it. The window
+// own — the same race the port exists to end. Its port disconnect says the
-// closing before any port connected is the one case with nothing else to speak
+// same thing this event does, in an order that is defined, so the disconnect is
-// for it, and is rejected here so the dApp is not left waiting on a window that
+// left to say it. The window closing before any port connected is the one case
-// is gone.
+// with nothing else to speak for it, and is rejected here so the dApp is not
+// left waiting on a window that is gone.
 if (windowsNs && windowsNs.onRemoved) {
     windowsNs.onRemoved.addListener((windowId) => {
         for (const [id, approval] of Object.entries(pendingApprovals)) {
             if (approval.windowId !== windowId) continue;
-            const decidedOnPort =
+            if (approval.type === "tx" || approval.type === "sign") {
-                approval.type !== "tx" && approval.type !== "sign";
+                approval.windowClosed = true;
-            if (decidedOnPort && approval.portConnected) continue;
+                updateToolbarPopup();
-            const rejection = abandonedResult(
+                continue;
-                approval,
+            }
-                APPROVAL_REJECTED_CODE,
+            if (approval.portConnected) continue;
-                APPROVAL_REJECTED_MESSAGE,
+            settleApproval(
+                id,
+                abandonedResult(
+                    approval,
+                    APPROVAL_REJECTED_CODE,
+                    APPROVAL_REJECTED_MESSAGE,
+                ),
             );
-            if (!settleApproval(id, rejection)) approval.windowClosed = true;
         }
     });
 }
@@ -1652,7 +1666,9 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 });
                 return false;
             }
-            return true;
+            // The popup waits for this answer before it closes its window.
+            sendResponse(null);
+            return false;
         }
 
         // The popup signs; it reports back here when it could not. Keep the
@@ -1852,7 +1868,8 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 });
                 return false;
             }
-            return true;
+            sendResponse(null);
+            return false;
         }
 
         // The popup signs; it reports back here when it could not. Keep the

src/background/state.js

@@ -18,11 +18,10 @@
 //   updateState(fn)   read fresh, apply fn to that fresh record, write it
 //                     back — all holding the lock every write of the stored
 //                     record takes, so no other write lands in between, by
-//                     the background or by any page except a page in a
+//                     the background or by any page (README, "Stored state
-//                     Firefox private window (README, "Stored state and its
+//                     and its version"). The read is one storage round trip
-//                     version"). The read is one storage round trip ahead of
+//                     ahead of the write rather than a page lifetime ahead of
-//                     the write rather than a page lifetime ahead of it
+//                     it (which is what made the popup's saveState() need a
-//                     (which is what made the popup's saveState() need a
 //                     per-field merge against a baseline at all).
 //
 // A handler that must both read and write therefore does its network work
@@ -73,8 +72,7 @@ async function updateStateOnce(mutate) {
 // src/shared/browserApi.js) is held from the read to the write: two
 // background turns, or a turn and a page's save, never interleave
 // (https://git.eeqj.de/sneak/AutistMask/issues/641). Every page's save waits
-// while it is held, except a page in a Firefox private window, which Firefox
+// while it is held (README, "Stored state and its version").
-// gives locks of its own (README, "Stored state and its version").
 //
 // `mutate` must also not call updateState() itself, directly or through
 // anything it awaits: the inner turn waits for the lock the outer one holds,

src/popup/index.html

@@ -43,6 +43,38 @@
             <!-- ============ WELCOME / FIRST USE ============ -->
             <div id="view-welcome" class="view hidden">
                 <p class="mb-3">Welcome! To get started, add a wallet.</p>
+                <div class="bg-well p-3 mx-1 mb-3">
+                    <p class="text-xs mb-2">
+                        This wallet sends your data only to the Ethereum RPC
+                        endpoint, unless you turn on one of these. You can
+                        change them later in Settings.
+                    </p>
+                    <label
+                        class="text-xs flex items-center gap-1 cursor-pointer mb-1"
+                    >
+                        <input type="checkbox" id="welcome-use-blockscout" />
+                        Use Blockscout
+                    </label>
+                    <p class="text-xs text-muted mb-2">
+                        Shows transaction history, transaction details and the
+                        tokens you have not tracked. Sends your addresses, and
+                        the hash of each transaction you open, to the Blockscout
+                        API.
+                    </p>
+                    <label
+                        class="text-xs flex items-center gap-1 cursor-pointer mb-1"
+                    >
+                        <input
+                            type="checkbox"
+                            id="welcome-check-recipients-on-etherscan"
+                        />
+                        Check recipients on Etherscan
+                    </label>
+                    <p class="text-xs text-muted">
+                        Sends each recipient's address to Etherscan to check it
+                        for a phishing or scam label.
+                    </p>
+                </div>
                 <button
                     id="btn-welcome-add"
                     class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
@@ -272,6 +304,10 @@
 
                 <!-- wallet list -->
                 <div id="wallet-list"></div>
+                <p id="home-tokens-note" class="text-xs text-muted py-1 hidden">
+                    Only tracked tokens are listed, because "Use Blockscout" is
+                    off in Settings.
+                </p>
 
                 <!-- recent transactions across all addresses -->
                 <div>
@@ -336,6 +372,13 @@
                     <div id="address-balances" class="min-h-[1.25rem]">
                         &nbsp;
                     </div>
+                    <p
+                        id="address-tokens-note"
+                        class="text-xs text-muted hidden"
+                    >
+                        Only tracked tokens are listed, because "Use Blockscout"
+                        is off in Settings.
+                    </p>
                 </div>
 
                 <!-- actions -->
@@ -526,12 +569,23 @@
                 </div>
                 <div class="mb-2">
                     <label class="block mb-1">What to send</label>
-                    <select
+                    <!-- The token dropdown and the line under it. Both are
-                        id="send-token"
+                    hidden when AddressToken opens Send for its own token. -->
-                        class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
+                    <div id="send-token-dropdown">
-                    >
+                        <select
-                        <option value="ETH">ETH</option>
+                            id="send-token"
-                    </select>
+                            class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
+                        >
+                            <option value="ETH">ETH</option>
+                        </select>
+                        <p
+                            id="send-tokens-note"
+                            class="text-xs text-muted hidden"
+                        >
+                            Only tracked tokens are listed, because "Use
+                            Blockscout" is off in Settings.
+                        </p>
+                    </div>
                     <div id="send-token-static" class="text-sm hidden"></div>
                 </div>
                 <div class="mb-2">
@@ -660,6 +714,13 @@
                         phishing/scam. Do not send funds to this address.
                     </div>
                 </div>
+                <p
+                    id="confirm-etherscan-note"
+                    class="mb-2 text-xs text-muted hidden"
+                >
+                    This address was not checked on Etherscan, because "Check
+                    recipients on Etherscan" is off in Settings.
+                </p>
                 <div
                     id="confirm-errors"
                     class="mb-2 border border-border border-dashed p-2 invisible min-h-[1.25rem]"
@@ -750,6 +811,7 @@
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">Amount</div>
                     <div id="wait-tx-summary" class="font-bold"></div>
+                    <div id="wait-tx-token-note"></div>
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">To</div>
@@ -796,6 +858,7 @@
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">Amount</div>
                     <div id="error-tx-summary" class="font-bold"></div>
+                    <div id="error-tx-token-note"></div>
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">To</div>
@@ -917,6 +980,23 @@
                     </button>
                 </div>
 
+                <div class="bg-well p-3 mx-1 mb-3">
+                    <h3 class="font-bold mb-1">Passwords</h3>
+                    <label
+                        class="text-xs flex items-center gap-1 cursor-pointer mb-1"
+                    >
+                        <input
+                            type="checkbox"
+                            id="settings-allow-weak-passwords"
+                        />
+                        Allow weak passwords
+                    </label>
+                    <p class="text-xs text-muted">
+                        Lets you choose a password shorter than 12 characters
+                        when you add a wallet.
+                    </p>
+                </div>
+
                 <div class="bg-well p-3 mx-1 mb-3">
                     <h3 class="font-bold mb-1">Tracked Tokens</h3>
                     <p class="text-xs text-muted mb-2">
@@ -1002,9 +1082,21 @@
 
                 <div class="bg-well p-3 mx-1 mb-3">
                     <h3 class="font-bold mb-1">Blockscout API</h3>
+                    <label
+                        class="text-xs flex items-center gap-1 cursor-pointer mb-1"
+                    >
+                        <input type="checkbox" id="settings-use-blockscout" />
+                        Use Blockscout
+                    </label>
+                    <p class="text-xs text-muted mb-2">
+                        Shows transaction history, transaction details and the
+                        tokens you have not tracked. Sends your addresses, and
+                        the hash of each transaction you open, to the Blockscout
+                        API below.
+                    </p>
                     <p class="text-xs text-muted mb-1">
-                        Used to fetch token balances and transaction history.
+                        Change the URL below if you run your own Blockscout
-                        Change this if you run your own Blockscout instance.
+                        instance.
                     </p>
                     <input
                         type="text"
@@ -1019,6 +1111,23 @@
                     </button>
                 </div>
 
+                <div class="bg-well p-3 mx-1 mb-3">
+                    <h3 class="font-bold mb-1">Etherscan</h3>
+                    <label
+                        class="text-xs flex items-center gap-1 cursor-pointer mb-1"
+                    >
+                        <input
+                            type="checkbox"
+                            id="settings-check-recipients-on-etherscan"
+                        />
+                        Check recipients on Etherscan
+                    </label>
+                    <p class="text-xs text-muted">
+                        Sends each recipient's address to Etherscan to check it
+                        for a phishing or scam label.
+                    </p>
+                </div>
+
                 <div class="bg-well p-3 mx-1 mb-3">
                     <h3 class="font-bold mb-1">Token Spam Protection</h3>
                     <p class="text-xs text-muted mb-2">
@@ -1291,6 +1400,13 @@
                 >
                     &nbsp;
                 </div>
+                <p
+                    id="delete-address-tokens-note"
+                    class="text-xs text-muted mb-2 hidden"
+                >
+                    Only tracked tokens are listed, because "Use Blockscout" is
+                    off in Settings.
+                </p>
                 <p class="text-xs text-muted mb-3">
                     A wallet always keeps at least one address. To remove the
                     last one, delete the whole wallet from Settings instead.
@@ -1504,6 +1620,16 @@
                     </div>
                 </div>
 
+                <!-- Shown in place of the block, decoded details, network
+                details and raw data, which only Blockscout gives. -->
+                <p
+                    id="tx-detail-blockscout-note"
+                    class="text-xs text-muted mx-1 mb-3 hidden"
+                >
+                    This screen shows no block, decoded details, network details
+                    or raw data, because "Use Blockscout" is off in Settings.
+                </p>
+
                 <!-- ── Decoded details ── -->
                 <div id="tx-detail-calldata-section" class="hidden">
                     <div class="bg-well p-3 mx-1 mb-3">

src/popup/index.js

@@ -5,12 +5,14 @@ const {
     state,
     saveState,
     onSaveFailure,
+    takeStoredNetwork,
     loadState,
 } = require("../shared/state");
 const { StateUnusableError } = require("../shared/stateSchema");
 const { log, setRuntimeDebug } = require("../shared/log");
 const { refreshPrices } = require("../shared/prices");
-const { refreshBalances } = require("../shared/balances");
+const { refreshBalances, dropUntrackedTokens } = require("../shared/balances");
+const { clearPopupCaches } = require("../shared/chainSwitch");
 const {
     $,
     showView,
@@ -22,6 +24,7 @@ const {
 } = require("./views/helpers");
 const { applyTheme } = require("./theme");
 const {
+    onStorageChanged,
     tabsGetCurrent,
     tabsGetZoom,
     windowsGetCurrent,
@@ -68,20 +71,28 @@ let refreshInFlight = false;
 // the recovery screen: there is no profile left to refresh.
 let refreshTimer = null;
 
+// The refresh first takes the stored network, "Use Blockscout" and "Check
+// recipients on Etherscan" (followStoredSettings() below). So the screens it
+// draws reflect any change saved elsewhere.
+//
 // The refresh writes into a copy of the wallets. Inside the save, under the
 // lock, its results are copied onto the address records in `state` only if the
 // network it ran on is still the active one, on this page and in the stored
 // record; the background's switch, after the user approves a site's request,
-// changes only the stored record. A switch while the refresh ran cleared every
+// reaches this page only after the stored record (followStoredSettings()).
-// address's balances (applyChainSwitchFields() in
+// A switch while the refresh ran cleared every address's balances
-// src/shared/chainSwitchFields.js), and the previous network's must not come
+// (applyChainSwitchFields() in src/shared/chainSwitchFields.js), and the
-// back over them (https://git.eeqj.de/sneak/AutistMask/issues/577). A dropped
+// previous network's must not come back over them
-// refresh is not recorded as done. Results are copied by address, so an address
+// (https://git.eeqj.de/sneak/AutistMask/issues/577). A dropped refresh is not
-// added or removed meanwhile is left as it is.
+// recorded as done. Results are copied by address, so an address added or
+// removed meanwhile is left as it is. Blockscout may have answered before the
+// user turned "Use Blockscout" off. So the save drops every token the user has
+// not tracked if the stored setting is off by then.
 async function doRefreshAndRender() {
     if (refreshInFlight) return;
     refreshInFlight = true;
     try {
+        await followStoredSettings();
         const networkId = state.networkId;
         const wallets = structuredClone(state.wallets);
         await Promise.all([
@@ -113,6 +124,9 @@ async function doRefreshAndRender() {
                     }
                 }
             }
+            if (!stored.useBlockscout) {
+                dropUntrackedTokens(state.wallets, stored.trackedTokens);
+            }
             state.lastBalanceRefresh = Date.now();
             return true;
         });
@@ -147,6 +161,7 @@ const ctx = {
     renderWalletList,
     doRefreshAndRender,
     startRefresh,
+    restoreView,
     pageClosed: pageClosed.signal,
     showAddWalletView: () => {
         pushCurrentView();
@@ -214,6 +229,47 @@ function fallbackView() {
     showView("main");
 }
 
+// When the background saves a network switch, once the user approves a site's
+// request, or another popup page saves one, this page follows the stored
+// record. It takes the network the record names as a save reads it, holding
+// the lock, so no later save of this page writes the previous network back, and
+// then leaves the page as a switch in Settings leaves it. This page's own
+// switch in Settings is made under the lock as well (onChainSwitch() in
+// src/shared/chainSwitch.js), so a record naming a network other than this
+// page's always holds a switch saved elsewhere, and a switch the user picks
+// here while this waits for the lock is made after it.
+//
+// Another page may change "Use Blockscout" or "Check recipients on Etherscan".
+// This page takes either change the same way and draws its screens again. This
+// page's own changes to the two settings are made under the lock too
+// (views/settings.js, views/welcome.js).
+async function followStoredSettings() {
+    let changed = false;
+    // A failed save is reported by saveState() itself: see onSaveFailure().
+    await saveState((stored) => {
+        if (stored.networkId !== state.networkId) {
+            settings.cutViewStack();
+            takeStoredNetwork(stored);
+            clearPopupCaches();
+            changed = true;
+        }
+        if (stored.useBlockscout !== state.useBlockscout) {
+            settings.setUseBlockscout(stored.useBlockscout);
+            changed = true;
+        }
+        if (
+            stored.checkRecipientsOnEtherscan !==
+            state.checkRecipientsOnEtherscan
+        ) {
+            state.checkRecipientsOnEtherscan =
+                stored.checkRecipientsOnEtherscan;
+            changed = true;
+        }
+        if (!changed) return false;
+    }).catch(() => {});
+    if (changed) settings.showNewSettings();
+}
+
 // The background opens the approval window as wide as the page, but the
 // browser counts the window's frame in that width, and a screen taller than
 // the window takes a vertical scrollbar out of it too. So once the screen is
@@ -225,9 +281,9 @@ function fallbackView() {
 // zoom it reports, 170% among them, so once the page has its new width (its
 // resize event) it is measured again, and the window widened again while the
 // page still falls short, three times at most. A window that cannot grow sends
-// no resize event, and the page stops there. The connection prompt can also
+// no resize event, and the page stops there. An approval can also show in the
-// show in the toolbar popup, whose window is the user's browser window; that
+// toolbar popup, whose window is the user's browser window; that one is left
-// one is left alone.
+// alone.
 async function widenApprovalWindow() {
     const page = document.documentElement;
     if (page.scrollWidth <= page.clientWidth) return;
@@ -358,8 +414,27 @@ async function init() {
     settingsAddToken.init(ctx);
     deleteAddress.init(ctx);
 
+    // This page follows a record only when its network, "Use Blockscout" or
+    // "Check recipients on Etherscan" differs from this page's. A record
+    // written by this page's own save matches this page. A record naming no
+    // network is no switch.
+    onStorageChanged((changes) => {
+        const written = changes.autistmask && changes.autistmask.newValue;
+        if (!written || !written.networkId) return;
+        if (
+            written.networkId !== state.networkId ||
+            written.useBlockscout !== state.useBlockscout ||
+            written.checkRecipientsOnEtherscan !==
+                state.checkRecipientsOnEtherscan
+        ) {
+            followStoredSettings();
+        }
+    });
+    // A change saved since loadState() above, before there was a listener.
+    followStoredSettings();
+
     if (!state.hasWallet) {
-        showView("welcome");
+        welcome.show();
     } else {
         renderWalletList();
         restoreView();

src/popup/viewRouter.js

@@ -38,11 +38,16 @@ function markViewRendered(view) {
     if (view) renderedViews.add(view);
 }
 
-// Begin a fresh page-load scope. The popup gets one by being loaded, and
+// Begin a fresh page-load scope. The popup gets one by being loaded. It also
-// asks for one when the user switches the network, because every screen
+// asks for one when every screen on the page is out of date:
-// then on the page shows the previous network (views/settings.js); the
+//
-// unit tests, which simulate several page loads against one module
+//   - after a network switch, since those screens show the previous network
-// instance, ask for one too.
+//     (showNewSettings() in views/settings.js)
+//   - after "Use Blockscout" or "Check recipients on Etherscan" changes, here
+//     or on another page, since those screens were drawn under the old setting
+//
+// The unit tests ask for one too. They simulate several page loads against one
+// module instance.
 function resetRenderedViews() {
     renderedViews.clear();
 }

src/popup/views/addWallet.js

@@ -132,7 +132,8 @@ function validatePassword() {
         showError("add-wallet-password-error", "Please choose a password.");
         return null;
     }
-    if (pw.length < 12) {
+    // "Allow weak passwords" in Settings lifts the 12-character minimum.
+    if (!state.allowWeakPasswords && pw.length < 12) {
         showError(
             "add-wallet-password-error",
             "Password must be at least 12 characters.",

src/popup/views/addressDetail.js

@@ -4,6 +4,7 @@ const {
     showFlash,
     balanceLinesForAddress,
     txCounterpartyHtml,
+    HISTORY_OFF_TEXT,
     addressTitle,
     escapeHtml,
     displaySymbol,
@@ -83,6 +84,8 @@ function show() {
                 ctx.showAddressToken();
             });
         });
+    // Only Blockscout reports the tokens the user has not tracked.
+    $("address-tokens-note").classList.toggle("hidden", !!state.useBlockscout);
     renderSendTokenSelect(addr);
     $("tx-list").innerHTML =
         '<div class="text-muted text-xs py-1">Loading...</div>';
@@ -155,6 +158,10 @@ async function loadTransactions(address) {
 
 function renderTransactions(txs) {
     const list = $("tx-list");
+    if (!state.useBlockscout) {
+        list.innerHTML = `<div class="text-muted text-xs py-1">${escapeHtml(HISTORY_OFF_TEXT)}</div>`;
+        return;
+    }
     if (txs.length === 0) {
         list.innerHTML =
             '<div class="text-muted text-xs py-1">No transactions found.</div>';
@@ -229,7 +236,7 @@ function init(_ctx) {
         }
         $("send-to").value = "";
         $("send-amount").value = "";
-        $("send-token").classList.remove("hidden");
+        $("send-token-dropdown").classList.remove("hidden");
         $("send-token-static").classList.add("hidden");
         updateSendBalance();
         resetSendValidation();

src/popup/views/addressToken.js

@@ -7,6 +7,7 @@ const {
     showFlash,
     flashCopyFeedback,
     txCounterpartyHtml,
+    HISTORY_OFF_TEXT,
     addressTitle,
     escapeHtml,
     displaySymbol,
@@ -239,6 +240,10 @@ async function loadTransactions(address, tokenId) {
 
 function renderTransactions(txs) {
     const list = $("address-token-tx-list");
+    if (!state.useBlockscout) {
+        list.innerHTML = `<div class="text-muted text-xs py-1">${escapeHtml(HISTORY_OFF_TEXT)}</div>`;
+        return;
+    }
     if (txs.length === 0) {
         list.innerHTML =
             '<div class="text-muted text-xs py-1">No transactions found.</div>';
@@ -324,7 +329,7 @@ function init(_ctx) {
             $("send-token").value = tokenId;
         }
         // Hide dropdown, show static token display
-        $("send-token").classList.add("hidden");
+        $("send-token-dropdown").classList.add("hidden");
         let staticHtml = `<div class="font-bold">${escapeHtml(displaySymbol(currentSymbol))}</div>`;
         if (tokenId !== "ETH") {
             staticHtml += `<div class="text-xs">${renderAddressHtml(tokenId)}</div>`;

src/popup/views/approval.js

@@ -11,6 +11,7 @@ const {
     onViewLeave,
     formatFee,
     tokenLabel,
+    blockscoutOffTokenNoteHtml,
     tokenSourcesByChainId,
 } = require("./helpers");
 const { state, saveState, currentNetwork } = require("../../shared/state");
@@ -54,7 +55,7 @@ const {
 } = require("../../shared/approvalVerify");
 const txStatus = require("./txStatus");
 const uniswap = require("../../shared/uniswap");
-const { notify, runtimeApi, sendMessage } = require("../../shared/browserApi");
+const { runtimeApi, sendMessage } = require("../../shared/browserApi");
 
 const erc20Iface = new Interface(ERC20_ABI);
 
@@ -401,6 +402,10 @@ function showTxApproval(details) {
             if (d.address) {
                 if (d.isToken) {
                     detailsHtml += `<div class="font-bold">${escapeHtml(tokenLabel(d.address, approvedTx.chainId) || "Unknown token")}</div>`;
+                    detailsHtml += blockscoutOffTokenNoteHtml(
+                        d.address,
+                        approvedTx.chainId,
+                    );
                 }
                 detailsHtml += approvalAddressHtml(
                     d.address,
@@ -623,10 +628,7 @@ function permitWarningHtml(types, primaryType, domain, message) {
             return "";
     }
 
-    const sources = {
+    const sources = tokenSourcesByChainId();
-        trackedTokens: state.trackedTokens,
-        wallets: state.wallets,
-    };
     const spender = addressOrNull(
         declaredField(types, primaryType, message, "spender")?.value,
     );
@@ -655,6 +657,7 @@ function permitWarningHtml(types, primaryType, domain, message) {
         html += `<div class="mb-2"><div>Token</div>`;
         if (token) {
             html += `<div>${escapeHtml(tokenLabel(token) || "Unknown token")}</div>`;
+            html += blockscoutOffTokenNoteHtml(token);
             html += approvalAddressHtml(token);
         } else {
             html += `<div>Unknown</div>`;
@@ -1139,12 +1142,21 @@ function init(_ctx) {
         }
     });
 
-    $("btn-reject-tx").addEventListener("click", () => {
+    // The window closes only once the background has the rejection. A message
-        notify({
+    // sent as the window closes can be lost, and a closed window does not
+    // reject the request. After Confirm, the background refuses a rejection
+    // while the transaction is being sent. The window then stays open and
+    // shows the background's message.
+    $("btn-reject-tx").addEventListener("click", async () => {
+        const response = await sendMessage({
             type: "AUTISTMASK_TX_RESPONSE",
             id: approvalId,
             approved: false,
-        });
+        }).catch(() => null);
+        if (response && response.error) {
+            showError("approve-tx-error", response.error);
+            return;
+        }
         window.close();
     });
 
@@ -1267,12 +1279,18 @@ function init(_ctx) {
         if (outcome.retryable) setSignButtonBusy(false);
     });
 
-    $("btn-reject-sign").addEventListener("click", () => {
+    // As for the transaction's Reject above. After Sign, the background
-        notify({
+    // refuses a rejection while the signature is being checked.
+    $("btn-reject-sign").addEventListener("click", async () => {
+        const response = await sendMessage({
             type: "AUTISTMASK_SIGN_RESPONSE",
             id: approvalId,
             approved: false,
-        });
+        }).catch(() => null);
+        if (response && response.error) {
+            showError("approve-sign-error", response.error);
+            return;
+        }
         window.close();
     });
 }

src/popup/views/confirmTx.js

@@ -334,6 +334,11 @@ function show(txInfo) {
     $("confirm-contract-warning").style.visibility = "hidden";
     $("confirm-burn-warning").style.visibility = "hidden";
     $("confirm-etherscan-warning").style.visibility = "hidden";
+    // While "Check recipients on Etherscan" is off, there is no Etherscan
+    // warning to reserve space for. A line in its place says the check is off.
+    const etherscanOn = !!state.checkRecipientsOnEtherscan;
+    $("confirm-etherscan-warning").classList.toggle("hidden", !etherscanOn);
+    $("confirm-etherscan-note").classList.toggle("hidden", etherscanOn);
 
     // Show burn warning via reserved element (in addition to inline warning)
     if (isBurnAddress(txInfo.to)) {

src/popup/views/deleteAddress.js

@@ -119,6 +119,11 @@ function show(walletIdx, addrIdx) {
 
     $("delete-address-recovery").textContent = recoveryPathText(wallet);
     $("delete-address-balance").innerHTML = balanceWarningHtml(addr);
+    // Only Blockscout reports the tokens the user has not tracked.
+    $("delete-address-tokens-note").classList.toggle(
+        "hidden",
+        !!state.useBlockscout,
+    );
 
     setFlash("");
     showView("delete-address-confirm");

src/popup/views/deleteWallet.js

@@ -16,6 +16,7 @@ const {
     broadcastActiveChanged,
 } = require("../../shared/walletDelete");
 const { INVISIBLE_CHARACTERS } = require("../../shared/symbolSpoof");
+const welcome = require("./welcome");
 
 let deleteWalletIndex = null;
 let lostPasswordIndex = null;
@@ -135,7 +136,7 @@ async function finishDelete(walletIdx) {
         // Save before broadcasting: the background reads the active
         // address back out of storage to build accountsChanged.
         if (activeAddressChanged) broadcastActiveChanged();
-        showView("welcome");
+        welcome.show();
         return;
     }
 

src/popup/views/helpers.js

@@ -21,7 +21,10 @@ const {
     truncateAmountNeverZero,
     isBelowOneMillionth,
 } = require("../../shared/amountDisplay");
-const { resolveTokenSymbol } = require("../../shared/approvalAmount");
+const {
+    resolveTokenDecimals,
+    resolveTokenSymbol,
+} = require("../../shared/approvalAmount");
 const { getProvider } = require("../../shared/balances");
 const { DEBUG } = require("../../shared/constants");
 const { escapeHtml } = require("../../shared/html");
@@ -306,10 +309,16 @@ function nativeCurrency() {
 // names a token on one network only, and every token balance held is the
 // active network's, so another network gets the tokens tracked on it
 // (state.networkTrackedTokens, see applyChainSwitchFields()) and no balances.
+//
+// The wallets' balances hold what Blockscout reported for each token. So the
+// wallets are returned only while "Use Blockscout" is on.
 function tokenSourcesByChainId(chainId) {
     const net = chainId ? networkByChainId(chainId) : currentNetwork();
     if (net && net.id === state.networkId) {
-        return { trackedTokens: state.trackedTokens, wallets: state.wallets };
+        return {
+            trackedTokens: state.trackedTokens,
+            wallets: state.useBlockscout ? state.wallets : [],
+        };
     }
     return {
         trackedTokens: (net && state.networkTrackedTokens[net.id]) || [],
@@ -317,11 +326,39 @@ function tokenSourcesByChainId(chainId) {
     };
 }
 
-// The symbol shown for a token line on the network with `chainId`, or on the
+// The line shown under a token while "Use Blockscout" is off. The token gets
-// active network when none is given: from the bundled list, the tokens the
+// the line only when the bundled list and the tracked tokens lack its name or
-// user tracks, and the explorer's report, the sources the amount line's scale
+// decimals. Otherwise this returns "". The token is a contract address on the
-// comes from. Null when no source names one, so the token lines keep saying
+// network with `chainId`, or on the active network when none is given. "ETH"
-// `Unknown token` for a token nothing knows.
+// and null are no contract, and get "". A token that is not text also gets "":
+// WaitTx and ErrorTx pass a token restored from storage unchecked.
+function blockscoutOffTokenNoteHtml(token, chainId) {
+    if (typeof token !== "string") return "";
+    if (state.useBlockscout || !token || token === "ETH") return "";
+    const sources = tokenSourcesByChainId(chainId);
+    if (
+        resolveTokenSymbol(token, sources) !== null &&
+        resolveTokenDecimals(token, sources) !== null
+    ) {
+        return "";
+    }
+    return (
+        '<div class="text-xs text-muted">Blockscout\'s report of your balances' +
+        ' is not used to name this token, because "Use Blockscout" is off in' +
+        " Settings.</div>"
+    );
+}
+
+// The symbol shown for a token line, from these sources in order:
+//
+// - the bundled list
+// - the tokens the user tracks
+// - the explorer's report, while "Use Blockscout" is on
+//
+// The network is the one with `chainId`, or the active network when none is
+// given. The amount line's scale comes from the same sources. Null when no
+// source names one, so the token lines keep saying `Unknown token` for a token
+// nothing knows.
 function tokenLabel(address, chainId) {
     return resolveTokenSymbol(address, tokenSourcesByChainId(chainId));
 }
@@ -534,6 +571,12 @@ function addressTitle(address, wallets) {
 const CONTRACT_CREATION_TEXT =
     "This transaction creates a new contract. It has no recipient.";
 
+// The line shown in place of the transaction history on Home, AddressDetail and
+// AddressToken while "Use Blockscout" is off. That history comes from
+// Blockscout alone.
+const HISTORY_OFF_TEXT =
+    'No transaction history is shown, because "Use Blockscout" is off in Settings.';
+
 // The last two lines of a transaction history row: the counterparty's colour
 // dot and name beside the amount, then its full address. A contract creation
 // the user sent has no counterparty (its `to` is ""), so its row has the
@@ -791,6 +834,7 @@ module.exports = {
     unknownableAmount,
     nativeCurrency,
     tokenSourcesByChainId,
+    blockscoutOffTokenNoteHtml,
     tokenLabel,
     formatFee,
     addressDotHtml,
@@ -799,6 +843,7 @@ module.exports = {
     displaySymbol,
     addressTitle,
     CONTRACT_CREATION_TEXT,
+    HISTORY_OFF_TEXT,
     txCounterpartyHtml,
     formatAddressHtml,
     renderAddressHtml,

src/popup/views/home.js

@@ -7,6 +7,7 @@ const {
     timeAgo,
     addressDotHtml,
     txCounterpartyHtml,
+    HISTORY_OFF_TEXT,
     addressTitle,
     escapeHtml,
     displaySymbol,
@@ -100,6 +101,10 @@ let homeTxs = [];
 function renderHomeTxList(ctx) {
     const list = $("home-tx-list");
     if (!list) return;
+    if (!state.useBlockscout) {
+        list.innerHTML = `<div class="text-muted text-xs py-1">${escapeHtml(HISTORY_OFF_TEXT)}</div>`;
+        return;
+    }
     if (homeTxs.length === 0) {
         list.innerHTML =
             '<div class="text-muted text-xs py-1">No transactions found.</div>';
@@ -300,6 +305,8 @@ function walletListHtml() {
 
 function render(ctx) {
     const container = $("wallet-list");
+    // Only Blockscout reports the tokens the user has not tracked.
+    $("home-tokens-note").classList.toggle("hidden", !!state.useBlockscout);
     if (state.wallets.length === 0) {
         container.innerHTML =
             '<p class="text-muted py-2">No wallets yet. Add one to get started.</p>';
@@ -447,7 +454,7 @@ function init(ctx) {
         }
         $("send-to").value = "";
         $("send-amount").value = "";
-        $("send-token").classList.remove("hidden");
+        $("send-token-dropdown").classList.remove("hidden");
         $("send-token-static").classList.add("hidden");
         renderSendTokenSelect(addr);
         updateSendBalance();

src/popup/views/send.js

@@ -10,6 +10,7 @@ const {
     renderAddressHtml,
     attachCopyHandlers,
     goBack,
+    tokenSourcesByChainId,
 } = require("./helpers");
 const { state, currentAddress } = require("../../shared/state");
 let ctx;
@@ -141,6 +142,8 @@ function updateToValidation() {
 }
 
 function renderSendTokenSelect(addr) {
+    // Only Blockscout reports the tokens the user has not tracked.
+    $("send-tokens-note").classList.toggle("hidden", !!state.useBlockscout);
     const sel = $("send-token");
     sel.innerHTML = `<option value="ETH">${escapeHtml(nativeCurrency())}</option>`;
     const fraudSet = new Set(
@@ -185,7 +188,9 @@ function renderSendTokenSelect(addr) {
 // so the transfer is encoded with the number the user read rather than with
 // whatever the contract answers at signing time (see
 // src/shared/transferAmount.js). balances.js is formatting one explorer row at
-// fetch time and cannot consult a state it is in the middle of replacing.
+// fetch time and cannot consult a state it is in the middle of replacing. As on
+// the approval screens, tokenSourcesByChainId() gives the wallets only while
+// "Use Blockscout" is on.
 //
 // The two resolutions can therefore differ, and where they do, the stored
 // `balance` is a quantity computed at a scale this screen has just declined to
@@ -198,10 +203,7 @@ function tokenBalanceAndDecimals(addr, token) {
     const tb = (addr.tokenBalances || []).find(
         (t) => t.address.toLowerCase() === token.toLowerCase(),
     );
-    const tokenDecimals = resolveTokenDecimals(token, {
+    const tokenDecimals = resolveTokenDecimals(token, tokenSourcesByChainId());
-        trackedTokens: state.trackedTokens,
-        wallets: state.wallets,
-    });
     if (!tb) return { tokenBalance: "0", tokenDecimals };
     if (tokenDecimals === null) return { tokenBalance: null, tokenDecimals };
     return { tokenBalance: tb.balance ?? null, tokenDecimals };
@@ -401,8 +403,11 @@ function init(_ctx) {
             try {
                 const provider = getProvider(state.rpcUrl, state.networkId);
                 const resolved = await provider.resolveName(to);
+                // getProvider() does not look up a name resolved off-chain,
+                // so such a name comes back with no address too. The message
+                // covers both, in the one line the flash area shows.
                 if (!resolved) {
-                    showFlash("That ENS name has no address.");
+                    showFlash("That ENS name has no on-chain address.");
                     return;
                 }
                 resolvedTo = resolved;
@@ -426,7 +431,7 @@ function init(_ctx) {
     });
 
     $("btn-send-back").addEventListener("click", () => {
-        $("send-token").classList.remove("hidden");
+        $("send-token-dropdown").classList.remove("hidden");
         $("send-token-static").classList.add("hidden");
         goBack();
     });

src/popup/views/settings.js

@@ -17,6 +17,7 @@ const {
 const { state, saveState, currentNetwork } = require("../../shared/state");
 const { onChainSwitch } = require("../../shared/chainSwitch");
 const { restorableStack } = require("../../shared/persistedState");
+const { dropUntrackedTokens } = require("../../shared/balances");
 const { resetRenderedViews, markViewRendered } = require("../viewRouter");
 const {
     log,
@@ -38,6 +39,8 @@ const {
 
 const { notify, sendMessage } = require("../../shared/browserApi");
 
+let ctx;
+
 let versionClickCount = 0;
 let versionClickTimer = null;
 
@@ -199,6 +202,10 @@ function show() {
     $("settings-rpc").value = state.rpcUrl;
     $("settings-blockscout").value = state.blockscoutUrl;
     $("settings-network").value = state.networkId;
+    // Set on every show, not only at init: Welcome can change these two.
+    $("settings-use-blockscout").checked = state.useBlockscout;
+    $("settings-check-recipients-on-etherscan").checked =
+        state.checkRecipientsOnEtherscan;
     renderTrackedTokens();
     renderSiteLists();
     renderWalletListSettings();
@@ -243,7 +250,77 @@ async function renderSiteLists() {
     );
 }
 
-function init(ctx) {
+// A network switch, made by the user here or saved by the background once the
+// user approved a site's request (src/popup/index.js), leaves every screen on
+// the page showing the previous network. Two functions leave the page as
+// README's Screen Map describes:
+//
+// - cutViewStack(), before the switch is saved, so that save keeps the cut for
+//   a popup closed straight after
+// - showNewSettings(), once `state` holds the new network
+//
+// The stack is cut at the first screen that cannot be rendered from saved
+// state, such as Send or AddToken, and at AddressToken unless it shows the
+// native token: any other token there was picked on the previous network, so
+// it is no longer selected either. Without a wallet the stack starts at
+// Welcome, which that cut would drop, and Welcome shows nothing from a network.
+// A change to "Use Blockscout" cuts the stack the same way (setUseBlockscout()
+// below).
+function cutViewStack() {
+    if (!state.hasWallet) return;
+    if (state.selectedToken !== "ETH") {
+        const tokenView = state.viewStack.indexOf("address-token");
+        if (tokenView !== -1) {
+            state.viewStack = state.viewStack.slice(0, tokenView);
+        }
+        state.selectedToken = null;
+    }
+    state.viewStack = restorableStack(state.viewStack, state.currentView);
+}
+
+// Sets "Use Blockscout" to `on` on this page. It is called inside a save,
+// holding the lock, for the user's change here or another page's
+// (followStoredSettings() in src/popup/index.js).
+//
+// Send's token dropdown was filled under the old setting, and Back cannot draw
+// Send again. So the stack is cut, as for a network switch. Turning the setting
+// off also drops every token the user has not tracked.
+function setUseBlockscout(on) {
+    state.useBlockscout = on;
+    cutViewStack();
+    if (!on) dropUntrackedTokens(state.wallets, state.trackedTokens);
+}
+
+// Draws the page again after a network switch, or after another page changed
+// "Use Blockscout" or "Check recipients on Etherscan". Every screen counts as
+// not yet rendered, so "Back" renders again any screen that a reopened popup
+// can render. Settings on top is brought up to date in place. Any other screen
+// is drawn again as a reopened popup draws it, which is Home for one that
+// cannot be rendered from saved state. Without a wallet any other screen is
+// Welcome or AddWallet. Back only unhides Welcome, so its two checkboxes are
+// set here.
+function showNewSettings() {
+    resetRenderedViews();
+    $("welcome-use-blockscout").checked = state.useBlockscout;
+    $("welcome-check-recipients-on-etherscan").checked =
+        state.checkRecipientsOnEtherscan;
+    if (state.currentView === "settings") {
+        markViewRendered("settings");
+        $("settings-network").value = state.networkId;
+        $("settings-rpc").value = state.rpcUrl;
+        $("settings-blockscout").value = state.blockscoutUrl;
+        $("settings-use-blockscout").checked = state.useBlockscout;
+        $("settings-check-recipients-on-etherscan").checked =
+            state.checkRecipientsOnEtherscan;
+        renderTrackedTokens();
+    } else if (state.hasWallet) {
+        ctx.restoreView();
+    }
+    updateDebugBanner(state.currentView);
+}
+
+function init(_ctx) {
+    ctx = _ctx;
     deleteWallet.init(ctx);
     showPhrase.init();
 
@@ -317,39 +394,49 @@ function init(ctx) {
         showFlash("Saved.");
     });
 
+    // Each change is made inside the save, holding the lock. So
+    // followStoredSettings() in src/popup/index.js never mistakes this page's
+    // unsaved change for one that another page saved.
+    //
+    // The screens under Settings were drawn under the old setting. So each
+    // change makes every screen but Settings count as not yet drawn, as a
+    // network switch does. Back then draws again any screen that a reopened
+    // popup can draw. Back only unhides Welcome, so its boxes are set here too.
+    $("settings-use-blockscout").addEventListener("change", async () => {
+        const on = $("settings-use-blockscout").checked;
+        await saveState(() => setUseBlockscout(on));
+        $("welcome-use-blockscout").checked = on;
+        resetRenderedViews();
+        markViewRendered("settings");
+    });
+
+    $("settings-check-recipients-on-etherscan").addEventListener(
+        "change",
+        async () => {
+            const on = $("settings-check-recipients-on-etherscan").checked;
+            await saveState(() => {
+                state.checkRecipientsOnEtherscan = on;
+            });
+            $("welcome-check-recipients-on-etherscan").checked = on;
+            resetRenderedViews();
+            markViewRendered("settings");
+        },
+    );
+
     const networkSelect = $("settings-network");
     networkSelect.addEventListener("change", async () => {
+        // Whether `state` already has the network picked is asked only once
+        // the switch holds the lock: while an earlier pick waits for it,
+        // `state` still has the network before that pick, and a pick back to
+        // that network must still be made.
         const newId = networkSelect.value;
-        if (newId === state.networkId) return;
+        cutViewStack();
-        // The screens beneath Settings show the previous network, so Back
-        // finds them as it does in a reopened popup: each is rendered again
-        // when Back lands on it, and the stack is cut at the first one that
-        // cannot be rendered from saved state, such as Send or AddToken. It
-        // is cut at AddressToken too, unless that shows the native token: any
-        // other token there was picked on the previous network. Without a
-        // wallet the stack starts at Welcome, which that cut would drop, and
-        // Welcome shows nothing from a network. The cut comes before the
-        // switch so that the switch's save keeps it for a popup closed
-        // straight after.
-        if (state.hasWallet) {
-            const tokenView = state.viewStack.indexOf("address-token");
-            if (tokenView !== -1 && state.selectedToken !== "ETH") {
-                state.viewStack = state.viewStack.slice(0, tokenView);
-            }
-            state.viewStack = restorableStack(state.viewStack, "settings");
-        }
         const net = await onChainSwitch(newId);
+        if (!net) return;
         // Open pages are told by the background, as after a site's approved
         // switch request.
         notify({ type: "AUTISTMASK_NETWORK_CHANGED", chainId: net.chainId });
-        resetRenderedViews();
+        showNewSettings();
-        // Settings itself, and the testnet banner above it, are brought up
-        // to date for the new network here.
-        markViewRendered("settings");
-        $("settings-rpc").value = state.rpcUrl;
-        $("settings-blockscout").value = state.blockscoutUrl;
-        renderTrackedTokens();
-        updateDebugBanner(state.currentView);
         showFlash("Switched to " + net.name + ".");
     });
 
@@ -412,6 +499,12 @@ function init(ctx) {
         await saveState();
     });
 
+    $("settings-allow-weak-passwords").checked = state.allowWeakPasswords;
+    $("settings-allow-weak-passwords").addEventListener("change", async () => {
+        state.allowWeakPasswords = $("settings-allow-weak-passwords").checked;
+        await saveState();
+    });
+
     $("btn-main-add-wallet").addEventListener("click", ctx.showAddWalletView);
 
     $("btn-settings-add-token").addEventListener(
@@ -484,4 +577,11 @@ function init(ctx) {
     });
 }
 
-module.exports = { init, show, renderSiteLists };
+module.exports = {
+    init,
+    show,
+    renderSiteLists,
+    cutViewStack,
+    setUseBlockscout,
+    showNewSettings,
+};

src/popup/views/stateRecovery.js

@@ -143,8 +143,6 @@ async function resetProfile() {
     try {
         // Under the lock every write of the stored record takes, so the erase
         // cannot land between another write's read and its write and be undone.
-        // A page in a Firefox private window is the exception: Firefox gives
-        // it locks of its own (README, "Stored state and its version").
         await withLock("autistmask", () => storageRemove("autistmask"));
     } catch (e) {
         log.errorf("state recovery: reset failed:", e);

src/popup/views/transactionDetail.js

@@ -26,6 +26,7 @@ const { state } = require("../../shared/state");
 const { nativeCurrencyByChainId } = require("../../shared/networks");
 const { formatEther, formatUnits } = require("ethers");
 const { log, debugFetch } = require("../../shared/log");
+const { storedSettingIsOn } = require("../../shared/storedSettings");
 const { decodeCalldata } = require("./approval");
 
 /**
@@ -172,7 +173,8 @@ function render() {
         }
     }
 
-    // Hide calldata and raw data sections; always fetch full tx details
+    // Hide the calldata and raw data sections. loadFullTxDetails() shows them
+    // once it has their data.
     const calldataSection = $("tx-detail-calldata-section");
     if (calldataSection) calldataSection.classList.add("hidden");
     const rawDataSection = $("tx-detail-rawdata-section");
@@ -191,6 +193,12 @@ function render() {
         if (el) el.classList.add("hidden");
     }
 
+    // The block, network details, decoded details and raw data come from
+    // Blockscout. While the setting is off, this line says why none is shown.
+    $("tx-detail-blockscout-note").classList.toggle(
+        "hidden",
+        !!state.useBlockscout,
+    );
     loadFullTxDetails(tx.hash, tx.chainId);
 
     const isoStr = isoDate(tx.timestamp);
@@ -303,7 +311,12 @@ function populateOnChainDetails(txData, chainId) {
     }
 }
 
+// Reads the block, network details and calldata from Blockscout, and decodes
+// the calldata. While the stored "Use Blockscout" is off, Blockscout is not
+// asked. An answer that lands after the setting went off is dropped
+// (src/shared/storedSettings.js). Either way none of them is shown.
 async function loadFullTxDetails(txHash, chainId) {
+    if (!(await storedSettingIsOn("useBlockscout"))) return;
     const section = $("tx-detail-calldata-section");
     const actionEl = $("tx-detail-calldata-action");
     const detailsEl = $("tx-detail-calldata-details");
@@ -319,6 +332,7 @@ async function loadFullTxDetails(txHash, chainId) {
         );
         if (!resp.ok) return;
         const txData = await resp.json();
+        if (!(await storedSettingIsOn("useBlockscout"))) return;
 
         // Populate on-chain detail fields (block, nonce, gas, fee)
         populateOnChainDetails(txData, chainId);

src/popup/views/txStatus.js

@@ -14,6 +14,7 @@ const {
     displaySymbol,
     clearViewStack,
     tokenLabel,
+    blockscoutOffTokenNoteHtml,
     reviewedNetworkProvider,
 } = require("./helpers");
 const { state } = require("../../shared/state");
@@ -108,6 +109,10 @@ function startWait(txInfo, txHash, broadcastTime, pollNow) {
     }
     $("wait-tx-summary").textContent =
         txInfo.amount + (symbol ? " " + symbol : "");
+    $("wait-tx-token-note").innerHTML = blockscoutOffTokenNoteHtml(
+        txInfo.token,
+        txInfo.chainId,
+    );
     $("wait-tx-to").innerHTML = toAddressHtml(txInfo.to, txInfo.chainId);
     $("wait-tx-hash").innerHTML = txHashHtml(txHash, txInfo.chainId);
     attachCopyHandlers("view-wait-tx");
@@ -215,9 +220,10 @@ function showWait(txInfo, txHash) {
 // init and leaving wait-tx on screen with no back control. A non-numeric
 // broadcastTime leaves an unexitable wait counting "NaNs". txInfo.chainId picks
 // the node the receipt is asked of and the explorer the links open, so it has
-// to name a network. txInfo.token and txInfo.tokenSymbol are deliberately
+// to name a network. txInfo.token and txInfo.tokenSymbol are not checked here.
-// unchecked: they are compared and coalesced rather than dereferenced, and
+// blockscoutOffTokenNoteHtml() shows no line for a token that is not text.
-// tokenSymbol is null for ETH.
+// Everything else only compares and coalesces them, and tokenSymbol is null for
+// ETH.
 function restoreWait() {
     const d = state.viewData;
     if (!d || !d.pendingWait) return false;
@@ -282,6 +288,7 @@ function decodedDetailsHtml(decoded, chainId) {
             if (d.isToken) {
                 const sym = tokenLabel(d.address, chainId) || "Unknown token";
                 html += `<div class="font-bold">${escapeHtml(sym)}</div>`;
+                html += blockscoutOffTokenNoteHtml(d.address, chainId);
                 html += toAddressHtml(d.address, chainId);
             } else {
                 html += toAddressHtml(d.address, chainId);
@@ -345,6 +352,7 @@ function showError(txInfo, txHash, message) {
     state.viewData = {
         amount: txInfo.amount,
         symbol: symbol,
+        token: txInfo.token,
         to: txInfo.to,
         hash: txHash || null,
         message: message,
@@ -358,6 +366,10 @@ function renderError() {
     if (!d || !d.message) return;
     $("error-tx-summary").textContent =
         d.amount + (d.symbol ? " " + d.symbol : "");
+    $("error-tx-token-note").innerHTML = blockscoutOffTokenNoteHtml(
+        d.token,
+        d.chainId,
+    );
     $("error-tx-to").innerHTML = toAddressHtml(d.to, d.chainId);
     $("error-tx-message").textContent = d.message;
 

src/popup/views/welcome.js

@@ -1,7 +1,37 @@
-const { $ } = require("./helpers");
+// The first screen, shown while there is no wallet. It offers "Use Blockscout"
+// and "Check recipients on Etherscan", which Settings offers too. Both are off
+// until the user ticks them.
 
-function init(ctx) {
+const { $, showView } = require("./helpers");
-    $("btn-welcome-add").addEventListener("click", ctx.showAddWalletView);
+const { state, saveState } = require("../../shared/state");
+
+function show() {
+    $("welcome-use-blockscout").checked = state.useBlockscout;
+    $("welcome-check-recipients-on-etherscan").checked =
+        state.checkRecipientsOnEtherscan;
+    showView("welcome");
 }
 
-module.exports = { init };
+// Each change is made inside the save, holding the lock, as Settings makes it.
+function init(ctx) {
+    $("btn-welcome-add").addEventListener("click", ctx.showAddWalletView);
+
+    $("welcome-use-blockscout").addEventListener("change", async () => {
+        const on = $("welcome-use-blockscout").checked;
+        await saveState(() => {
+            state.useBlockscout = on;
+        });
+    });
+
+    $("welcome-check-recipients-on-etherscan").addEventListener(
+        "change",
+        async () => {
+            const on = $("welcome-check-recipients-on-etherscan").checked;
+            await saveState(() => {
+                state.checkRecipientsOnEtherscan = on;
+            });
+        },
+    );
+}
+
+module.exports = { init, show };

src/shared/balances.js

@@ -1,5 +1,10 @@
-// Balance fetching: ETH balances via RPC, ERC-20 token balances via
+// Balance fetching:
-// Blockscout, ENS reverse lookup via RPC.
+//
+//   - ETH balances, and the balances of the tokens the user tracks, via RPC
+//   - the other ERC-20 token balances and the holder counts via Blockscout,
+//     while the user has "Use Blockscout" on. Those balances are dropped when
+//     the setting is off.
+//   - ENS reverse lookup via RPC
 
 const {
     JsonRpcProvider,
@@ -17,6 +22,7 @@ const { LOW_HOLDER_THRESHOLD, parseHoldersCount } = require("./holders");
 const { isSpoofedSymbol } = require("./symbolSpoof");
 const { toDecimals } = require("./transferAmount");
 const { resolveTokenDecimals } = require("./approvalAmount");
+const { storedSettingIsOn } = require("./storedSettings");
 
 // Use a static network to skip auto-detection (which can fail and cause
 // "could not coalesce error" on some RPC endpoints like Cloudflare).
@@ -36,9 +42,18 @@ const { resolveTokenDecimals } = require("./approvalAmount");
 // ethers knows chains this wallet does not, so an id that is not one of ours
 // is a caller bug and must not resolve to a working provider for some other
 // chain.
+//
+// `disableCcipRead` keeps every ENS lookup on the RPC endpoint. A resolver can
+// say a name is resolved off-chain and give a web address for it. By default
+// ethers then fetches that address straight from the browser, sending the name
+// being looked up. For the reverse lookup of the user's addresses, the name sent
+// is the user's own (https://git.eeqj.de/sneak/AutistMask/issues/668). With the
+// flag set, such a name does not resolve.
 function getProvider(rpcUrl, networkId) {
     const net = Network.from(requireNetworkId(networkId).id);
-    return new JsonRpcProvider(rpcUrl, net, { staticNetwork: net });
+    const provider = new JsonRpcProvider(rpcUrl, net, { staticNetwork: net });
+    provider.disableCcipRead = true;
+    return provider;
 }
 
 function requireNetworkId(networkId) {
@@ -80,8 +95,16 @@ function rawUnits(value) {
 
 // Fetch token balances for a single address from Blockscout.
 // Returns [{ address, name, symbol, decimals, balance, holders }].
+//
+// While the stored "Use Blockscout" is off, Blockscout is not asked. An answer
+// that lands after the setting went off is dropped
+// (src/shared/storedSettings.js). Either way this returns an empty list, so
+// only tracked tokens are listed.
+//
 // Filters out spam: only shows tokens that are in the known token list,
-// explicitly tracked by the user, or have >= 1000 holders.
+// explicitly tracked by the user, or have >= 1000 holders. A tracked token's
+// balance is read through the RPC endpoint instead, and its row here gives that
+// entry its holder count and `decimals` (fetchTrackedTokenBalances()).
 //
 // `decimals` and `balance` are each null when the answer is unknown, the same
 // way `holders` already is. Absence is never filled in here: this is the
@@ -96,6 +119,7 @@ async function fetchTokenBalances(
     trackedTokens,
     signal,
 ) {
+    if (!(await storedSettingIsOn("useBlockscout"))) return [];
     try {
         const resp = await debugFetch(
             blockscoutUrl + "/addresses/" + address + "/token-balances",
@@ -105,6 +129,7 @@ async function fetchTokenBalances(
             return null;
         }
         const items = await resp.json();
+        if (!(await storedSettingIsOn("useBlockscout"))) return [];
         if (!Array.isArray(items)) return null;
 
         const trackedSet = new Set(
@@ -205,8 +230,96 @@ async function fetchTokenBalances(
     }
 }
 
-// Fetch ETH balances, ENS names, and ERC-20 token balances for all addresses.
+// The entries at `address` of the tokens the user tracks, shaped as
+// fetchTokenBalances() returns them, for the tokens the address holds.
+//
+// The balance is read with balanceOf through the RPC endpoint. The name and
+// symbol are the tracked token's. `decimals` and `holders` are those of
+// Blockscout's entry for the token in `explorerRequest`, this refresh's
+// fetchTokenBalances() for the address; while Blockscout fails they are kept
+// from the token's entry in `previous`, the address's entries before this
+// refresh. The balance is stated at the scale the screens read the token at
+// (resolveTokenDecimals()): the bundled list's, then the one the tracked token
+// records, then Blockscout's, as in fetchTokenBalances().
+//
+// A token whose balanceOf fails keeps its entry in `previous`, as a failed ETH
+// balance keeps its figure, or takes Blockscout's entry from this refresh when
+// it has none. The failure is logged. A balance of zero gets no entry, as a
+// zero Blockscout reports gets none: the balance lists take a tracked token's
+// zero from the tracked list. A token whose symbol the spoof rule refuses gets
+// no entry either, as in fetchTokenBalances().
+//
 // `signal` is as for fetchTokenBalances().
+async function fetchTrackedTokenBalances(
+    provider,
+    address,
+    trackedTokens,
+    previous,
+    explorerRequest,
+    signal,
+) {
+    const listed = trackedTokens.filter(
+        (token) => !isSpoofedSymbol(token.symbol, token.address),
+    );
+    // Each token's balanceOf answer, or null where it failed.
+    const balances = await Promise.all(
+        listed.map(async (token) => {
+            try {
+                const contract = new Contract(
+                    token.address,
+                    ERC20_ABI,
+                    provider,
+                );
+                return await contract.balanceOf(address);
+            } catch (e) {
+                if (!signal?.aborted) {
+                    log.errorf(
+                        "token balance failed",
+                        address,
+                        token.address,
+                        e.shortMessage || e.message,
+                    );
+                }
+                return null;
+            }
+        }),
+    );
+    const explorerRows = await explorerRequest;
+    const reported = explorerRows ?? previous;
+
+    const rows = [];
+    listed.forEach((token, i) => {
+        const lower = token.address.toLowerCase();
+        const entryIn = (list) =>
+            list.find((row) => String(row.address).toLowerCase() === lower);
+        const raw = balances[i];
+        if (raw === null) {
+            const kept = entryIn(previous) || entryIn(explorerRows || []);
+            if (kept) rows.push(kept);
+            return;
+        }
+        if (raw === 0n) return;
+        const entry = entryIn(reported);
+        const decimals = entry ? entry.decimals : null;
+        const known = resolveTokenDecimals(lower, { trackedTokens });
+        const scale = known !== null ? known : decimals;
+        rows.push({
+            address: token.address,
+            name: token.name || "",
+            symbol: token.symbol || "???",
+            decimals: decimals,
+            // null when nothing knows the scale: a holding whose amount
+            // cannot be stated, never a zero.
+            balance: scale === null ? null : formatTokenBalance(raw, scale),
+            holders: entry ? entry.holders : null,
+        });
+    });
+    return rows;
+}
+
+// Fetch ETH balances, ENS names, and ERC-20 token balances for all addresses.
+// `trackedTokens` are the tokens tracked on the active network. `signal` is as
+// for fetchTokenBalances().
 async function refreshBalances(
     wallets,
     rpcUrl,
@@ -217,6 +330,8 @@ async function refreshBalances(
 ) {
     log.debugf("refreshBalances start, rpc:", urlOrigin(rpcUrl));
     const provider = getProvider(rpcUrl, networkId);
+    const tracked = trackedTokens || [];
+    const trackedSet = new Set(tracked.map((t) => t.address.toLowerCase()));
     const updates = [];
 
     for (const wallet of wallets) {
@@ -266,23 +381,43 @@ async function refreshBalances(
                     }),
             );
 
-            // ERC-20 token balances via Blockscout
+            // ERC-20 token balances: the tracked tokens' through the RPC
+            // endpoint, and from Blockscout the tokens the user has not
+            // tracked. When Blockscout fails, the untracked rows from before
+            // this refresh stay. While "Use Blockscout" is off, there are no
+            // untracked rows. The Blockscout request is started first and
+            // handed to fetchTrackedTokenBalances() too, which waits for it
+            // after sending its balanceOf reads, so the two run side by side.
+            const previous = addr.tokenBalances || [];
+            const explorerRequest = fetchTokenBalances(
+                addr.address,
+                blockscoutUrl,
+                tracked,
+                signal,
+            );
             updates.push(
-                fetchTokenBalances(
+                Promise.all([
-                    addr.address,
+                    fetchTrackedTokenBalances(
-                    blockscoutUrl,
+                        provider,
-                    trackedTokens,
+                        addr.address,
-                    signal,
+                        tracked,
-                ).then((balances) => {
+                        previous,
-                    if (balances !== null) {
+                        explorerRequest,
-                        addr.tokenBalances = balances;
+                        signal,
-                        log.debugf(
+                    ),
-                            "Token balances",
+                    explorerRequest,
-                            addr.address,
+                ]).then(([trackedRows, explorerRows]) => {
-                            balances.length,
+                    const untrackedRows = (explorerRows ?? previous).filter(
-                            "tokens",
+                        (row) =>
-                        );
+                            !trackedSet.has(String(row.address).toLowerCase()),
-                    }
+                    );
+                    addr.tokenBalances = trackedRows.concat(untrackedRows);
+                    log.debugf(
+                        "Token balances",
+                        addr.address,
+                        addr.tokenBalances.length,
+                        "tokens",
+                    );
                 }),
             );
         }
@@ -292,6 +427,20 @@ async function refreshBalances(
     log.debugf("refreshBalances done");
 }
 
+// Drops the balance of each token not in `trackedTokens` from every address.
+// Callers run it while "Use Blockscout" is off, since only Blockscout reports
+// those tokens.
+function dropUntrackedTokens(wallets, trackedTokens) {
+    const tracked = new Set(trackedTokens.map((t) => t.address.toLowerCase()));
+    for (const wallet of wallets) {
+        for (const addr of wallet.addresses || []) {
+            addr.tokenBalances = (addr.tokenBalances || []).filter((row) =>
+                tracked.has(String(row.address).toLowerCase()),
+            );
+        }
+    }
+}
+
 // Look up token metadata from its contract.
 // Calls symbol() and decimals() to verify it implements ERC-20.
 // `signal` is as for fetchTokenBalances().
@@ -410,6 +559,7 @@ async function scanForAddresses(xpub, rpcUrl, networkId, signal, gapLimit = 5) {
 module.exports = {
     fetchTokenBalances,
     refreshBalances,
+    dropUntrackedTokens,
     lookupTokenInfo,
     getProvider,
     scanForAddresses,

src/shared/browserApi.js

@@ -224,6 +224,19 @@ function storageRemove(keys) {
     return Promise.resolve(storage.remove(keys));
 }
 
+/**
+ * Call `listener` after every write to `storage.local`, whether this page,
+ * another page or the background made it, with what the write changed, as the
+ * browser reports it: `{ [key]: { oldValue, newValue } }`.
+ *
+ * @param {function(Object): void} listener
+ */
+function onStorageChanged(listener) {
+    namespaceMember("storage").onChanged.addListener((changes, areaName) => {
+        if (areaName === "local") listener(changes);
+    });
+}
+
 /**
  * Run `fn` while holding the browser's lock called `name`
  * (`navigator.locks`), and settle as `fn` settles. Every page of the extension
@@ -385,6 +398,7 @@ module.exports = {
     getPlatformInfo,
     hasBrowserNamespace,
     notify,
+    onStorageChanged,
     runtimeApi,
     sendMessage,
     sessionStorageGet,

src/shared/chainSwitch.js

@@ -1,8 +1,18 @@
-// Consolidated chain-switch handler for the popup.
+// The popup's network switch.
 //
-// Every state change required when the active network changes is
+// A network switch reaches the popup's `state` in one of two ways:
-// performed here so that callers (settings UI, future chain additions) all go
+//
-// through a single code path.
+// - onChainSwitch() below makes the switch the user picks in Settings, with
+//   applyChainSwitchFields() (chainSwitchFields.js).
+// - followStoredSettings() in src/popup/index.js takes a switch the background
+//   or another popup page saved, from the stored record, with
+//   takeStoredNetwork() (state.js), which copies it with
+//   copyChainSwitchFields() (chainSwitchFields.js).
+//
+// Both change `state` inside a save, holding the lock, and both reset the
+// popup's own caches through clearPopupCaches(), so a reset added there
+// reaches both. A field applyChainSwitchFields() sets has to be copied by
+// copyChainSwitchFields() too.
 //
 // Adding a new chain (e.g. ETC) requires only a new entry in
 // networks.js — no per-caller wiring is needed.
@@ -20,22 +30,32 @@
 const { applyChainSwitchFields } = require("./chainSwitchFields");
 const { clearPrices } = require("./prices");
 
+// The popup's own caches a network switch resets. Prices are chain-specific
+// (testnet tokens are worthless, ETC has different pricing, etc.). In-memory
+// and per bundle, so this is the popup's own cache — the only context that
+// ever fills it.
+function clearPopupCaches() {
+    clearPrices();
+}
+
 // Switch the active chain and reset all chain-specific cached state.
-// Returns the network configuration object for the new chain.
+// Returns the network configuration object for the new chain, or null when
+// `state` already has that network once the save holds the lock, and nothing
+// is switched.
+//
+// `state` is switched inside the save that stores the switch, holding the
+// lock, so it is never switched while a follow of a switch saved elsewhere
+// waits for the lock (followStoredSettings() in src/popup/index.js): that
+// follow runs first, and this switch is made after it.
 async function onChainSwitch(newNetworkId) {
     const { state, saveState } = require("./state");
-
+    let net = null;
-    const net = applyChainSwitchFields(state, newNetworkId);
+    await saveState(() => {
-
+        if (state.networkId === newNetworkId) return false;
-    // --- price cache ---
+        net = applyChainSwitchFields(state, newNetworkId);
-    // Prices are chain-specific (testnet tokens are worthless,
+        clearPopupCaches();
-    // ETC has different pricing, etc.). In-memory and per bundle, so this is
+    });
-    // the popup's own cache — the only context that ever fills it.
-    clearPrices();
-
-    await saveState();
-
     return net;
 }
 
-module.exports = { onChainSwitch };
+module.exports = { onChainSwitch, clearPopupCaches };

src/shared/chainSwitchFields.js

@@ -7,7 +7,7 @@
 // the singleton and saves; the background applies it to the detached record of
 // its own read-modify-write (src/background/state.js).
 //
-// Everything here is synchronous and touches nothing but the object it is
+// Everything here is synchronous and touches nothing but the objects it is
 // given: no storage, no caches, no imports beyond the network table. That is
 // what makes it usable on a record that has been read fresh from storage
 // microseconds earlier and is about to be written back.
@@ -76,4 +76,33 @@ function applyChainSwitchFields(s, newNetworkId) {
     return net;
 }
 
-module.exports = { applyChainSwitchFields };
+// Give `s` every field applyChainSwitchFields() sets, as `switched` holds it:
+// the popup takes a switch the background saved from the stored record this
+// way, rather than performing it again (takeStoredNetwork() in
+// src/shared/state.js). Balances are taken by address, and an address
+// `switched` does not have keeps none.
+function copyChainSwitchFields(s, switched) {
+    s.networkEndpoints = switched.networkEndpoints;
+    s.networkTrackedTokens = switched.networkTrackedTokens;
+    s.trackedTokens = switched.trackedTokens;
+    s.networkId = switched.networkId;
+    s.rpcUrl = switched.rpcUrl;
+    s.blockscoutUrl = switched.blockscoutUrl;
+    s.lastBalanceRefresh = switched.lastBalanceRefresh;
+    s.tokenHolderCache = switched.tokenHolderCache;
+    s.fraudContracts = switched.fraudContracts;
+
+    const stored = new Map();
+    for (const wallet of switched.wallets) {
+        for (const addr of wallet.addresses) stored.set(addr.address, addr);
+    }
+    for (const wallet of s.wallets) {
+        for (const addr of wallet.addresses) {
+            const got = stored.get(addr.address);
+            addr.balance = got ? got.balance : "0";
+            addr.tokenBalances = got ? got.tokenBalances : [];
+        }
+    }
+}
+
+module.exports = { applyChainSwitchFields, copyChainSwitchFields };

src/shared/etherscanLabels.js

@@ -3,6 +3,7 @@
 // This is a best-effort enrichment: network failures return null silently.
 
 const { networkByChainId } = require("./networks");
+const { storedSettingIsOn } = require("./storedSettings");
 
 // Patterns in the page title that indicate a flagged address.
 // Title format: "Fake_Phishing184810 | Address: 0x... | Etherscan"
@@ -78,12 +79,19 @@ function parseEtherscanPage(html) {
  * when it is omitted: etherscan.io on mainnet, sepolia.etherscan.io on
  * Sepolia.
  *
+ * While the stored "Check recipients on Etherscan" is off, Etherscan is not
+ * asked. An answer that lands after the setting went off is dropped
+ * (src/shared/storedSettings.js). Either way the answer is null.
+ *
  * @param {string} address - Ethereum address to check.
  * @param {string} [chainId] - Chain id of the network to look it up on.
  * @returns {Promise<{type: string, message: string, severity: string}|null>}
  */
 async function checkEtherscanLabel(address, chainId) {
     try {
+        if (!(await storedSettingIsOn("checkRecipientsOnEtherscan"))) {
+            return null;
+        }
         // Lazy require to avoid pulling in chrome.storage at module scope
         // (which breaks unit tests that only exercise parseEtherscanPage).
         const { currentNetwork } = require("./state");
@@ -94,6 +102,9 @@ async function checkEtherscanLabel(address, chainId) {
         });
         if (!resp.ok) return null;
         const html = await resp.text();
+        if (!(await storedSettingIsOn("checkRecipientsOnEtherscan"))) {
+            return null;
+        }
         const result = parseEtherscanPage(html);
         if (result.isPhishing) {
             return {

src/shared/persistedState.js

@@ -48,6 +48,17 @@ const DEFAULT_STATE = {
     hideDustTransactions: true,
     dustThresholdGwei: 100000,
     utcTimestamps: false,
+    // "Use Blockscout" and "Check recipients on Etherscan" in Settings. Each
+    // setting applies to every network. Both are off until the user turns them
+    // on. With "Use Blockscout" on, Blockscout is sent the user's addresses and
+    // the hash of each transaction opened. With "Check recipients on
+    // Etherscan" on, Etherscan is sent the recipient's address and nothing
+    // else.
+    useBlockscout: false,
+    checkRecipientsOnEtherscan: false,
+    // "Allow weak passwords" in Settings. While it is off, AddWallet refuses a
+    // password shorter than 12 characters.
+    allowWeakPasswords: false,
     fraudContracts: [],
     tokenHolderCache: {},
     theme: "system",
@@ -406,6 +417,13 @@ function normalizePersisted(saved) {
             : 100000;
     out.utcTimestamps =
         saved.utcTimestamps !== undefined ? saved.utcTimestamps : false;
+    // Anything but true is off: each setting lets a request reach another
+    // service.
+    out.useBlockscout = saved.useBlockscout === true;
+    out.checkRecipientsOnEtherscan = saved.checkRecipientsOnEtherscan === true;
+    // Anything but true is off: the setting lets AddWallet accept a short
+    // password.
+    out.allowWeakPasswords = saved.allowWeakPasswords === true;
     // A list of contract addresses, floored the same way: send.js builds its
     // fraud set as `(state.fraudContracts || []).map((a) => a.toLowerCase())`
     // and filterTransactions() maps the same list through normalizeAddress(),

src/shared/state.js

@@ -23,6 +23,7 @@
 // guarantee.
 
 const { networkById } = require("./networks");
+const { copyChainSwitchFields } = require("./chainSwitchFields");
 const {
     DEFAULT_STATE,
     PERSISTED_FIELDS,
@@ -125,8 +126,10 @@ function currentNetwork() {
 }
 
 // The persisted fields as this page held them when its last loadState()
-// finished, or when its last successful saveState() began. saveState() diffs
+// finished, or when its last successful saveState() began, with any network
-// the live state against this to find only the fields THIS page changed since.
+// switch saved elsewhere that this page has taken since (takeStoredNetwork()).
+// saveState() diffs the live state against this to find only the fields THIS
+// page changed since.
 //
 // Deep-cloned, not a reference: callers mutate persisted objects and arrays
 // in place (state.wallets.push(...)), and a reference baseline would mutate
@@ -466,7 +469,11 @@ function mergeNetworkEndpoints(base, ours, theirs) {
 // exists to remove, just delayed and confined to one page instead of two
 // (caught by tests/txStatus.test.js). A page's live picture of a field it
 // does not own goes on being whatever its last loadState() saw, same as
-// before this fix; only the persisted record is guaranteed current.
+// before this fix; only the persisted record is guaranteed current. Three
+// fields are the exceptions: the network, "Use Blockscout" and "Check
+// recipients on Etherscan". Through `beforeWrite`, the popup takes a change to
+// any of them that another context saved (followStoredSettings() in
+// src/popup/index.js).
 async function saveStateOnce(beforeWrite) {
     const result = await storageGet("autistmask");
     // The record in storage right now is about to be merged into and written
@@ -574,9 +581,7 @@ function reportSaveFailure(err) {
 // Each save runs start to finish holding the lock every write of the stored
 // record takes (withLock() in src/shared/browserApi.js), so no write by
 // another page or the background lands between its read and its write and is
-// lost (https://git.eeqj.de/sneak/AutistMask/issues/641). A page in a Firefox
+// lost (https://git.eeqj.de/sneak/AutistMask/issues/641).
-// private window is the exception: Firefox gives it locks of its own (README,
-// "Stored state and its version").
 //
 // The same lock orders this page's own saves. showView() calls saveState() on
 // every navigation without awaiting it, so two saves from one page can be
@@ -597,6 +602,17 @@ function saveState(beforeWrite) {
     return turn;
 }
 
+// Give this page the network switch held by `stored`, a record a save of this
+// page has just read (followStoredSettings() in src/popup/index.js calls this
+// from `beforeWrite`), in `state` and in `baseline` alike, as loadState() does
+// with a whole record. The switch is then not this page's own change, even when
+// that save fails to write: a later switch back to the previous network still
+// differs from `baseline`, and is stored.
+function takeStoredNetwork(stored) {
+    copyChainSwitchFields(rawState, stored);
+    copyChainSwitchFields(baseline, structuredClone(stored));
+}
+
 // Rejects with StateUnusableError for a stored record this build cannot make
 // sense of. Nothing is assigned and `loaded` stays false in that case, so a
 // caller that ignores the rejection gets StateNotLoadedError on the first
@@ -642,6 +658,7 @@ module.exports = {
     state,
     saveState,
     onSaveFailure,
+    takeStoredNetwork,
     loadState,
     currentAddress,
     currentNetwork,

src/shared/storedSettings.js

@@ -0,0 +1,27 @@
+// Reads "Use Blockscout" or "Check recipients on Etherscan" from the stored
+// profile.
+//
+// Before each request that sends the user's data to Blockscout or Etherscan, the
+// wallet reads that service's setting from storage. The wallet reads the setting
+// again when the answer lands. While the setting is off, no such request is
+// made, and an answer that lands after the setting went off is dropped. A page's
+// own copy of the setting is not used, because another page may have just
+// changed it.
+
+const { storageGet } = require("./browserApi");
+const { normalizePersisted } = require("./persistedState");
+
+// Whether the setting `name` is on in the stored profile. `name` is
+// "useBlockscout" or "checkRecipientsOnEtherscan". The profile is read through
+// normalizePersisted(), as a load reads it, so only a stored true is on. A
+// failed read counts as off.
+async function storedSettingIsOn(name) {
+    try {
+        const { autistmask } = await storageGet("autistmask");
+        return normalizePersisted(autistmask)[name];
+    } catch {
+        return false;
+    }
+}
+
+module.exports = { storedSettingIsOn };

src/shared/transactions.js

@@ -21,6 +21,7 @@ const { toDecimals } = require("./transferAmount");
 // detail view is the authoritative record and already shows exact precision.
 const { truncateAmount: formatTxValue } = require("./amountDisplay");
 const { routerRelease } = require("./uniswap");
+const { storedSettingIsOn } = require("./storedSettings");
 
 // Ethereum addresses are case-insensitive: EIP-55 mixed case is a checksum
 // over the address, not part of its identity.  Every address comparison in
@@ -235,12 +236,17 @@ function mergeTransactions(txs, tokenTransfers) {
 // `chainId` is the chain id of the network `blockscoutUrl` serves. Every entry
 // carries it, and a native entry is labelled with that network's
 // `nativeCurrency` from networks.js (`ETH`, `SepoliaETH`).
+//
+// While the stored "Use Blockscout" is off, Blockscout is not asked. An answer
+// that lands after the setting went off is dropped
+// (src/shared/storedSettings.js). Either way the answer is an empty list.
 async function fetchRecentTransactions(
     address,
     blockscoutUrl,
     chainId,
     count = 25,
 ) {
+    if (!(await storedSettingIsOn("useBlockscout"))) return [];
     log.debugf("fetchRecentTransactions", address);
     const addrLower = normalizeAddress(address);
 
@@ -271,6 +277,7 @@ async function fetchRecentTransactions(
 
     const txJson = txResp.ok ? await txResp.json() : {};
     const ttJson = ttResp.ok ? await ttResp.json() : {};
+    if (!(await storedSettingIsOn("useBlockscout"))) return [];
 
     const txs = mergeTransactions(
         (txJson.items || []).map((tx) => parseTx(tx, addrLower, chainId)),

src/shared/uniswap.js

@@ -336,7 +336,8 @@ const UNNAMED_CURRENCY = "Unknown (not named in the calldata)";
 // currencies, and those commands may name one, so saying the calldata did not
 // name it would be false. The Paid to line uses it too, when a step may pay an
 // address this decoder did not read, and so do the lines for what a step
-// takes from the sender, when this decoder does not know it.
+// takes from the sender, when this decoder does not know it, and for what a
+// permit it could not read allows.
 const UNDECODED_CURRENCY = "Unknown (could not be decoded)";
 
 // The Paid to line for each token paid to the router, the swap's output or
@@ -494,8 +495,9 @@ function amountText(raw, info) {
     };
 }
 
-// The line giving a moved token under `label`, in the shape of the Token In
+// The line giving a moved token, or the token of a permit, under `label`, in
-// line, so the screens show it as they show that one. ETH has no address.
+// the shape of the Token In line, so the screens show it as they show that
+// one. ETH has no address.
 function tokenMovedLine(label, token, sources) {
     const info = tokenInfo(token, sources);
     if (!present(info.address)) {
@@ -527,6 +529,32 @@ function decodePermit2(input) {
     }
 }
 
+// Decode PERMIT2_PERMIT_BATCH (command 0x03) input bytes into the allowances
+// it grants, one for each token it names, all for its one spender, in the
+// shape decodePermit2() returns. Each release's
+// `contracts/base/Dispatcher.sol`, at the commit linked for it above, hands
+// Permit2 the batch in this shape.
+// ABI: (((address token, uint160 amount, uint48 expiration, uint48 nonce)[],
+//        address spender, uint256 sigDeadline), bytes signature)
+function decodePermit2Batch(input) {
+    try {
+        const d = coder.decode(
+            [
+                "tuple(tuple(address,uint160,uint48,uint48)[],address,uint256)",
+                "bytes",
+            ],
+            input,
+        );
+        return d[0][0].map((details) => ({
+            token: details[0],
+            amount: details[1],
+            spender: d[0][1],
+        }));
+    } catch {
+        return null;
+    }
+}
+
 // Decode BALANCE_CHECK_ERC20 (command 0x0e) input bytes. The router passes the
 // check when `owner` holds at least `minBalance` of `token`, and reads `owner`
 // as written, without map(), on every release that has the command:
@@ -596,12 +624,14 @@ function decodeV2SwapExactOut(input) {
 // token(20) ...), or null when it is not one token followed by whole hops of
 // a fee and a token (40 hex digits, then 46 per hop). The router reads only
 // whole hops and ignores any bytes after the last one, so the last 20 bytes
-// of such a path are not the token it reads there.
+// of such a path are not the token it reads there. Both are checksummed, as
+// the ABI decoder gives every other address, so a token reads the same on
+// every line.
 function decodeV3Path(pathHex) {
     const hex = pathHex.startsWith("0x") ? pathHex.slice(2) : pathHex;
     if (hex.length < 40 || (hex.length - 40) % 46 !== 0) return null;
-    const first = "0x" + hex.slice(0, 40);
+    const first = getAddress("0x" + hex.slice(0, 40));
-    const last = "0x" + hex.slice(-40);
+    const last = getAddress("0x" + hex.slice(-40));
     return { first, last };
 }
 
@@ -923,7 +953,9 @@ function totalAmount(amounts) {
 // 2. Amount is the amountIn of the swap action that spends Token In. If
 //    several exact-in actions spend it, each with a stated amount, it is
 //    their sum; in any other case there is none. Min. received is the same
-//    for amountOutMin and the actions that buy Token Out.
+//    for amountOutMin and the actions that buy Token Out, except that there
+//    is none when a swap action in the step also spends Token Out: the step
+//    then does not pay out all that those actions buy.
 // 3. If any swap action in the step cannot be read, only SETTLE, SETTLE_ALL,
 //    TAKE and TAKE_ALL name the sides, and there is no Amount or Min.
 //    received.
@@ -1157,11 +1189,13 @@ function decodeV4Swap(input) {
         const boughtOnly = currenciesNotIn(bought, spent);
         if (present(takeToken) || boughtOnly.length === 1) {
             tokenOut = present(takeToken) ? takeToken : boughtOnly[0];
-            amountOutMin = totalAmount(
+            if (!spent.includes(tokenOut)) {
-                swaps
+                amountOutMin = totalAmount(
-                    .filter((s) => s.tokenOut === tokenOut)
+                    swaps
-                    .map((s) => s.amountOutMin),
+                        .filter((s) => s.tokenOut === tokenOut)
-            );
+                        .map((s) => s.amountOutMin),
+                );
+            }
         }
 
         return {
@@ -1204,13 +1238,26 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         let inputToken = null;
         let inputAmount = null;
         let inputEstablished = false;
-        // Whether the user pays the V4 step that set the input side any of
+        // Whether the user pays the step that set the input side: a V2 or V3
-        // its input currency (see decodeV4Swap()). Only a V4 step can set the
+        // swap step with `payerIsUser` true, a V4 step the user pays some of
-        // input side with no amount, the one case in which this is read.
+        // its input currency (see decodeV4Swap()), or a WRAP_ETH, whose ETH
+        // comes from the transaction's value. A step paid from the router
+        // takes nothing from the sender.
         let inputPaidByUser = false;
-        // The last PERMIT2_PERMIT this decoder read, or null (see
+        // The recipient of a WRAP_ETH that set the input side, as written,
-        // permitStands after the loop).
+        // when it is not the router; otherwise null. That WRAP_ETH pays its
+        // WETH there, not to a swap step (see the Moved to lines).
+        let wrapEthRecipient = null;
+        // The last PERMIT2_PERMIT this decoder read before a step set the
+        // input side, or null (see permitStands after the loop).
         let permit = null;
+        // Every allowance a PERMIT2_PERMIT or PERMIT2_PERMIT_BATCH grants,
+        // before a step set the input side or after, in step order, as
+        // { token, amount, spender, step }. A permit or batch whose input
+        // this decoder cannot read is one with a null token, amount and
+        // spender. Each but a permit whose amount is the Amount figure gets
+        // lines of its own (see after the PERMIT2_TRANSFER_FROM lines).
+        const permits = [];
         // The index of each step this decoder did not read in full: a
         // command it does not read, a step whose input it cannot read, in
         // whole or in part, and one it fails on (see permitStands).
@@ -1268,8 +1315,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // when no earlier hop set it. A half the establishing hop did not
         // state stays null and the line says so, rather than being filled in
         // from a different hop. A PERMIT2_PERMIT sets no side here: after the
-        // loop, the last one read names Token In, and the Amount line is
+        // loop, one whose amount stands as the Amount figure names Token In,
-        // formed there, in one place (see permitStands).
+        // and the Amount line is formed there, in one place (see
+        // permitStands).
         const setInput = (token, amount) => {
             inputToken = present(token) ? token : null;
             inputAmount = present(amount) ? amount : null;
@@ -1292,15 +1340,18 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         };
 
         // What the steps take from the sender beyond the amount of the step
-        // that sets the input side, as { token, amount }, in step order.
+        // that sets the input side, as { token, amount, atMost }, in step
-        // After the loop each joins the Amount line or gets lines of its own
+        // order. After the loop each joins the Amount line or gets lines of
-        // (see permitStands).
+        // its own (see permitStands). A take with `atMost` set takes at most
+        // its amount, and always gets lines of its own.
         const userPaid = [];
         // A swap step the user pays for (`payerIsUser` true) takes `amount`
-        // of `token` from the sender. A V2 exact-in of ALREADY_PAID takes
+        // of `token` from the sender, or at most that when `atMost` is set. A
-        // nothing.
+        // V2 exact-in of ALREADY_PAID takes nothing.
-        const addUserPaid = (token, amount) => {
+        const addUserPaid = (token, amount, atMost = false) => {
-            if (amount !== ALREADY_PAID) userPaid.push({ token, amount });
+            if (amount !== ALREADY_PAID) {
+                userPaid.push({ token, amount, atMost });
+            }
         };
         // A step may take from the sender what this decoder did not read: a
         // V4 step whose input or one of whose SETTLEs or SETTLE_ALLs it
@@ -1313,6 +1364,15 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         const spentUnread = () => {
             userPaid.push({ token: null, amount: null });
         };
+        // A PERMIT2_PERMIT or PERMIT2_PERMIT_BATCH at `step` whose input this
+        // decoder cannot read may let any spender take any amount of any
+        // token: one line says so, there is no Amount line, whose figure may
+        // then be too low, and the minimum reads Min. paid out (see
+        // toAnotherSpender).
+        const permitUnread = (step) => {
+            permits.push({ token: null, amount: null, spender: null, step });
+            stepsUnread.push(step);
+        };
 
         // Who the steps pay, in whichever step and of whatever token.
         // MSG_SENDER is the sender. The router itself, as ADDRESS_THIS or by
@@ -1465,24 +1525,44 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                 } else if (command === "PERMIT2_PERMIT") {
                     const p = decodePermit2(inputs[i]);
                     if (p) {
+                        permits.push({ ...p, step: i });
+                        keepsRouterWeth = true;
+                    } else {
+                        permitUnread(i);
+                    }
+                    // Only a permit whose amount stands as the Amount figure
+                    // names Token In (see permitStands). Every other permit,
+                    // before the step that sets the input side or after it,
+                    // leaves Token In and Amount as they read with no permit
+                    // and gets lines of its own. One after a step set the input
+                    // side never stands, so only one before it is kept here.
+                    if (p && !inputEstablished) {
                         // Whether a step before it took its token, or may
-                        // have: the step that set the input side or one in
+                        // have: one in `userPaid`, `movedIntoRouter` or
-                        // `userPaid`, when its token is the permit's or not
+                        // `movedFromSender`, when its token is the permit's
-                        // known.
+                        // or not known. No step has set the input side yet.
                         const mayBeItsToken = (token) =>
                             !present(token) || sameAddress(token, p.token);
-                        const tookBefore =
+                        const tookBefore = [
-                            (inputEstablished && mayBeItsToken(inputToken)) ||
+                            ...userPaid,
-                            userPaid.some((t) => mayBeItsToken(t.token));
+                            ...movedIntoRouter,
+                            ...movedFromSender,
+                        ].some((t) => mayBeItsToken(t.token));
                         permit = {
                             ...p,
                             step: i,
                             allowedToFail,
                             beforeEveryTake: !tookBefore,
                         };
-                        keepsRouterWeth = true;
+                    }
+                } else if (command === "PERMIT2_PERMIT_BATCH") {
+                    // Each allowance it grants gets the lines of a permit
+                    // whose amount does not stand. It pays nobody.
+                    const batch = decodePermit2Batch(inputs[i]);
+                    if (batch) {
+                        permits.push(...batch.map((p) => ({ ...p, step: i })));
                     } else {
-                        stepsUnread.push(i);
+                        permitUnread(i);
                     }
                 } else if (command === "PERMIT2_TRANSFER_FROM") {
                     const p = decodePermit2TransferFrom(inputs[i]);
@@ -1556,6 +1636,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     if (s) {
                         if (!inputEstablished) {
                             setInputOnce(s.tokenIn, s.amountIn);
+                            inputPaidByUser = s.payerIsUser;
                         } else if (s.payerIsUser) {
                             addUserPaid(s.tokenIn, s.amountIn);
                         }
@@ -1579,6 +1660,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     if (s) {
                         if (!inputEstablished) {
                             setInputOnce(s.tokenIn, s.amountIn);
+                            inputPaidByUser = s.payerIsUser;
                         } else if (s.payerIsUser) {
                             addUserPaid(s.tokenIn, s.amountIn);
                         }
@@ -1610,6 +1692,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     if (s) {
                         if (!inputEstablished) {
                             setInputOnce(s.tokenIn, s.amountInMax);
+                            inputPaidByUser = s.payerIsUser;
                         } else if (s.payerIsUser) {
                             addUserPaid(s.tokenIn, s.amountInMax);
                         }
@@ -1705,10 +1788,16 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                 } else if (command === "WRAP_ETH") {
                     const w = decodeWrapEth(inputs[i]);
                     if (w) {
-                        setInputOnce(
+                        if (!inputEstablished) {
-                            "0x0000000000000000000000000000000000000000",
+                            setInputOnce(
-                            w.amount,
+                                "0x0000000000000000000000000000000000000000",
-                        );
+                                w.amount,
+                            );
+                            inputPaidByUser = true;
+                            if (!isRouter(w.recipient)) {
+                                wrapEthRecipient = w.recipient;
+                            }
+                        }
                         addPayee(w.recipient);
                         // CONTRACT_BALANCE wraps all the router's ETH.
                         if (w.amount === CONTRACT_BALANCE) {
@@ -1736,6 +1825,14 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                 } else if (command === "V4_SWAP") {
                     const v4 = decodeV4Swap(inputs[i]);
                     const inputSetBefore = inputEstablished;
+                    // V4Router pays a SETTLE of ETH from the router's own
+                    // ETH, whichever payer it names. When the router may hold
+                    // ETH from an earlier step, that ETH may pay some of the
+                    // ETH that the user pays this step. The sender then pays
+                    // at most the step's amount.
+                    const routerMayHoldEth = heldByRouter.has(
+                        "0x0000000000000000000000000000000000000000",
+                    );
                     if (v4) {
                         // Each SETTLE paid from the router spends the amount
                         // decodeV4Swap() says it pays.
@@ -1826,7 +1923,13 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     if (v4) {
                         for (const p of v4.paidByUser) {
                             if (setInputHere && p === paidIn) continue;
-                            addUserPaid(p.currency, p.amount);
+                            addUserPaid(
+                                p.currency,
+                                p.amount,
+                                routerMayHoldEth &&
+                                    p.currency ===
+                                        "0x0000000000000000000000000000000000000000",
+                            );
                         }
                     }
                     if (!v4 || v4.settleUnread) {
@@ -1892,8 +1995,8 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     }
                 } else {
                     // Any other step may pay an address this decoder does not
-                    // read: PERMIT2_PERMIT_BATCH and the NFT commands among
+                    // read: the NFT commands among them, and a type the
-                    // them, and a type the release names no command for.
+                    // release names no command for.
                     payeeUnread = true;
                     stepsUnread.push(i);
                 }
@@ -1937,20 +2040,29 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // being of another token or coming after an amount that is not a
         // quantity (a V4 open delta, ALREADY_PAID, or none stated), gets
         // lines of its own. One whose amount is not known also leaves the
-        // total unknown, with no figure.
+        // total unknown, with no figure. A take of at most its amount (see
+        // userPaid) is never added, and gets lines of its own too.
         //
-        // The last PERMIT2_PERMIT read names Token In. Its amount stands as
+        // A PERMIT2_PERMIT names Token In only when its amount stands as the
-        // the Amount figure in place of the total only in the plain shape of
+        // Amount figure in place of the total, which it does only in the
-        // Uniswap's own routes: it is the only PERMIT2_PERMIT, its spender is
+        // plain shape of Uniswap's own routes: it comes before the step that
+        // set the input side, it is the only PERMIT2_PERMIT in the
+        // transaction and there is no PERMIT2_PERMIT_BATCH, its spender is
         // the router, the router may not let it fail, no step before it took
-        // its token or one not known, and this decoder read every step after
+        // its token or one not known (a PERMIT2_TRANSFER_FROM of its token
-        // it in full (see stepsUnread). Permit2 then lets the router take no
+        // included), and this decoder read every step after it in full (see
-        // more of the token than that amount, so the permit covers every take
+        // stepsUnread). Permit2 then lets the router take no more of the token
-        // of it. A later step this decoder did not read may raise what Permit2
+        // than that amount, so the permit covers every take of it. A step
-        // lets the router take, as a PERMIT2_PERMIT_BATCH can. A step that
+        // before it takes under whatever allowance the router already had, so
-        // may take from the sender what this decoder did not read leaves no
+        // it may take more. A later permit or batch, or a later step this
-        // figure, permit or not (see spentUnread()), and an EXECUTE_SUB_PLAN
+        // decoder did not read, may raise what Permit2 lets the router take.
-        // step leaves both sides unknown (below).
+        // Every other PERMIT2_PERMIT leaves Token In and the Amount line as
+        // they read with no permit, and gets lines of its own below. A step
+        // that may take from the sender what this decoder did not read leaves
+        // no figure, permit or not (see spentUnread()), and so do a permit
+        // or batch whose input it cannot read (see permitUnread()) and an
+        // allowance of Token In to another spender (see toAnotherSpender). An
+        // EXECUTE_SUB_PLAN step leaves both sides unknown (below).
         const stepCommands = Array.from(
             commandsBytes,
             (b) => commands[b & commandTypeMask],
@@ -1958,15 +2070,24 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         const permitStands =
             permit !== null &&
             stepCommands.filter((c) => c === "PERMIT2_PERMIT").length === 1 &&
+            !stepCommands.includes("PERMIT2_PERMIT_BATCH") &&
             sameAddress(permit.spender, toAddress) &&
             !permit.allowedToFail &&
             permit.beforeEveryTake &&
             !stepsUnread.some((step) => step > permit.step);
         // What the steps take that the Amount line does not give, as
-        // { token, amount }. A null token is a step this decoder did not read
+        // { token, amount, atMost, recipient }. A null token is a step this
-        // (see spentUnread()), or a token it does not know.
+        // decoder did not read (see spentUnread()), or a token it does not
+        // know. `atMost` is as in `userPaid`. Only the take of a WRAP_ETH that
+        // pays elsewhere has a recipient (see wrapEthRecipient).
         const spentFromSender = [];
         let total = null;
+        // The takes from the sender that `total` adds up, each a quantity, in
+        // the shape of `spentFromSender`. When there is no Amount line, each
+        // gets lines of its own (see below). The amount of a step that set
+        // the input side and is paid from the router counts in `total` but is
+        // not among them.
+        const inTotal = [];
         // Whether the step that set the input side counts as a take from the
         // sender, which may get lines of its own. The amount it stated counts
         // whoever pays it. Stating none, it counts only when the user pays it
@@ -1977,26 +2098,39 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // The take of the step that set the input side, when the total
         // starts from it and it stated no amount (see below), or null.
         let firstTakeUnstated = null;
-        if (permit === null || sameAddress(inputToken, permit.token)) {
+        if (!permitStands || sameAddress(inputToken, permit.token)) {
             total = inputAmount;
+            if (typeof inputAmount === "bigint" && inputPaidByUser) {
+                inTotal.push({
+                    token: inputToken,
+                    amount: inputAmount,
+                    recipient: wrapEthRecipient,
+                });
+            }
             if (hasFirstTake && !present(inputAmount)) {
                 firstTakeUnstated = { token: inputToken, amount: null };
             }
         } else if (hasFirstTake) {
             // The step that set the input side spent a token other than the
-            // permit's, or one not known, so the total starts with no figure.
+            // permit's, or one not known, so its amount gets lines of its own.
-            spentFromSender.push({ token: inputToken, amount: inputAmount });
+            spentFromSender.push({
+                token: inputToken,
+                amount: inputAmount,
+                recipient: wrapEthRecipient,
+            });
         }
-        if (permit !== null) inputToken = permit.token;
+        if (permitStands) inputToken = permit.token;
         for (const t of userPaid) {
             const ofTokenIn = sameAddress(t.token, inputToken);
             if (ofTokenIn && permitStands) continue;
             if (
                 ofTokenIn &&
+                !t.atMost &&
                 typeof total === "bigint" &&
                 typeof t.amount === "bigint"
             ) {
                 total += t.amount;
+                inTotal.push(t);
                 continue;
             }
             spentFromSender.push(t);
@@ -2020,10 +2154,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         }
 
         // The commands of an EXECUTE_SUB_PLAN step may spend the user's tokens
-        // or pay the user, before or after any other step, and a permit among
+        // or pay the user, before or after any other step. What the other
-        // them would name Token In. What the other steps state is
+        // steps state is then not the whole swap, so both sides are set
-        // then not the whole swap, so both sides are set unknown, with no
+        // unknown, with no figure, wherever the step stands.
-        // figure, wherever the step stands.
         if (hasSubPlan) {
             inputToken = null;
             inputAmount = null;
@@ -2097,8 +2230,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // V2's already-paid zero, neither of which is a quantity at all (see
         // OPEN_DELTA and ALREADY_PAID), and an unbounded permit. Those two
         // tests come first — the sentinels are not bigints and cannot be
-        // compared with one.
+        // compared with one. `atMost` says the amount is a maximum (see
-        const spentText = (amount, info) => {
+        // userPaid).
+        const spentText = (amount, info, atMost = false) => {
             if (amount === OPEN_DELTA) {
                 return { raw: OPEN_DELTA_AMOUNT, display: OPEN_DELTA_AMOUNT };
             }
@@ -2111,7 +2245,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             if (amount >= MAX_UINT160) {
                 return { raw: "Unlimited", display: "Unlimited" };
             }
-            if (hasV2OrV3ExactOut) {
+            if (hasV2OrV3ExactOut || atMost) {
                 // A V2 or V3 exact-out swap spends at most this figure,
                 // whichever steps gave it (an amountInMax, the WRAP_ETH of a
                 // swap paid in ETH, a permit, or several steps' total), so it
@@ -2126,12 +2260,30 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             return amountText(amount, info);
         };
 
+        // Each allowance to a spender other than the router. Code that a step
+        // runs, such as a V4 pool's hook or a token's own code, can call that
+        // spender, which can then take up to the allowance from the sender
+        // before the transaction ends. A permit or batch this decoder could
+        // not read may be to any spender, of any token.
+        const toAnotherSpender = permits.filter(
+            (p) => !sameAddress(p.spender, toAddress),
+        );
+
         // A null token in `spentFromSender`, a step this decoder did not read
-        // or a token it does not know, leaves no Amount figure, which may
+        // or a token it does not know, and an allowance to another spender
-        // then be too low.
+        // that may be of Token In, leave no Amount figure, which may then be
+        // too low. With no Amount line, each take the total adds up gets
+        // lines of its own, first, so that every amount this decoder read is
+        // shown.
         if (
             present(inputAmount) &&
-            spentFromSender.every((s) => present(s.token))
+            spentFromSender.every((s) => present(s.token)) &&
+            toAnotherSpender.every(
+                (p) =>
+                    present(p.token) &&
+                    present(inputToken) &&
+                    !sameAddress(p.token, inputToken),
+            )
         ) {
             const amount = spentText(inputAmount, inInfo);
             details.push({
@@ -2139,25 +2291,40 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                 value: amount.display,
                 rawValue: amount.raw,
             });
+        } else {
+            spentFromSender.unshift(...inTotal);
         }
 
         // What steps take from the sender beyond the Amount line, in the shape
         // of the lines below for a PERMIT2_TRANSFER_FROM. An amount this
         // decoder does not know is said so, and a step it did not read gets
-        // that one line alone.
+        // that one line alone. A take with no recipient goes to the swap step
+        // that spends it. A take with a recipient goes to that recipient;
+        // `MSG_SENDER` means the sender.
         for (const s of spentFromSender) {
             details.push({
                 label: "Moved from the sender",
                 value: present(s.amount)
-                    ? spentText(s.amount, tokenInfo(s.token, sources)).display
+                    ? spentText(s.amount, tokenInfo(s.token, sources), s.atMost)
+                          .display
                     : UNDECODED_CURRENCY,
             });
             if (present(s.token)) {
                 details.push(tokenMovedLine("Token moved", s.token, sources));
-                details.push({
+                if (!present(s.recipient)) {
-                    label: "Moved to",
+                    details.push({
-                    value: "The swap step that spends it",
+                        label: "Moved to",
-                });
+                        value: "The swap step that spends it",
+                    });
+                } else if (s.recipient.toLowerCase() === MSG_SENDER) {
+                    details.push({ label: "Moved to", value: "The sender" });
+                } else {
+                    details.push({
+                        label: "Moved to",
+                        value: s.recipient,
+                        address: s.recipient,
+                    });
+                }
             }
         }
 
@@ -2181,6 +2348,40 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             );
         }
 
+        // What each allowance of a PERMIT2_PERMIT or PERMIT2_PERMIT_BATCH lets
+        // its spender take: its amount, its token and the spender, an address
+        // on a line of its own. Permit2's maximum is unbounded. Only a permit
+        // whose amount stands as the Amount figure (see permitStands) gets
+        // none: that line already gives its amount and Token In its token,
+        // and its spender is the router. Every other allowance, one after the
+        // step that set the input side included, gets these lines, so nothing
+        // it lets anyone take goes unstated. A permit or batch this decoder
+        // could not read gets one line saying so.
+        for (const p of permits) {
+            if (permitStands && p.step === permit.step) continue;
+            if (!present(p.token)) {
+                details.push({
+                    label: "Permit2 allowance",
+                    value: UNDECODED_CURRENCY,
+                });
+                continue;
+            }
+            details.push({
+                label: "Permit2 allowance",
+                value:
+                    p.amount >= MAX_UINT160
+                        ? "Unlimited"
+                        : amountText(p.amount, tokenInfo(p.token, sources))
+                              .display,
+            });
+            details.push(tokenMovedLine("Allowance token", p.token, sources));
+            details.push({
+                label: "Allowance spender",
+                value: p.spender,
+                address: p.spender,
+            });
+        }
+
         // Keyed on the address, not the symbol: a token absent from the
         // bundled list has no symbol, and gating the line on one dropped it
         // entirely, leaving a Min. received figure with nothing saying what is
@@ -2216,9 +2417,10 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // step pays the bridge, when one moves the sender's tokens into the
         // router, when a token stays in the router, and when a payout could
         // not be read. The output is received by the sender only when some
-        // step pays the sender and there is no such line. When no step names
+        // step pays the sender, there is no such line, and no allowance goes
-        // anyone paid, one line says so. `paidTo` holds these lines and the
+        // to another spender (see toAnotherSpender). When no step names anyone
-        // token line after each line about a token in the router.
+        // paid, one line says so. `paidTo` holds these lines and the token
+        // line after each line about a token in the router.
         const outputHeld =
             present(outputToken) && heldByRouter.has(outputToken.toLowerCase());
         const paidTo = paidElsewhere.map((address) => ({
@@ -2265,7 +2467,10 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         if (payeeUnread) {
             paidTo.push({ label: "Paid to", value: UNDECODED_CURRENCY });
         }
-        const received = paidToSender && paidTo.length === 0;
+        const received =
+            paidToSender &&
+            paidTo.length === 0 &&
+            toAnotherSpender.length === 0;
         if (!paidToSender && paidTo.length === 0) {
             paidTo.push({ label: "Paid to", value: UNNAMED_CURRENCY });
         }

tests/alarms.test.js

@@ -41,6 +41,8 @@ jest.mock("../src/shared/balances", () => ({
     refreshBalances: jest.fn(async () => {
         mockBalanceRefreshAt.push(Date.now());
     }),
+    dropUntrackedTokens: jest.requireActual("../src/shared/balances")
+        .dropUntrackedTokens,
     getProvider: jest.fn(() => ({})),
 }));
 

tests/allowWeakPasswords.test.js

@@ -0,0 +1,87 @@
+// "Allow weak passwords" in Settings is off until the user ticks it. While it
+// is off, AddWallet refuses a password shorter than 12 characters. While it is
+// on, AddWallet accepts any password that is not empty
+// (https://git.eeqj.de/sneak/AutistMask/issues/674). These boot the real popup,
+// set the checkbox in Settings as the user does, and then add a wallet.
+
+jest.mock("../src/shared/vault", () => ({
+    decryptWithPassword: jest.fn(),
+    encryptWithPassword: jest.fn(async () => ({
+        salt: "salt",
+        nonce: "nonce",
+        ciphertext: "ciphertext",
+    })),
+}));
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+} = require("./support/popupBoot");
+
+const CHECKBOX = "settings-allow-weak-passwords";
+const ERROR = "add-wallet-password-error";
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// Boots a popup that holds one wallet and opens Settings, where the checkbox
+// starts unticked. Ticks it when `allow` is true. Then opens AddWallet and
+// presses the die for a recovery phrase.
+async function openAddWallet(allow) {
+    const page = await bootPopup(unversionedValidProfile());
+    await page.click("btn-settings");
+    const checkbox = page.node(CHECKBOX);
+    expect(checkbox.checked).toBe(false);
+    if (allow) {
+        checkbox.checked = true;
+        for (const fn of checkbox.listeners.change) await fn();
+        expect(page.storage.read("autistmask").allowWeakPasswords).toBe(true);
+    }
+    await page.click("btn-main-add-wallet");
+    await page.click("btn-generate-phrase");
+    return page;
+}
+
+// Types `password` into both password fields and presses Import.
+async function importWith(page, password) {
+    page.node("add-wallet-password").value = password;
+    page.node("add-wallet-password-confirm").value = password;
+    await page.click("btn-add-wallet-confirm");
+}
+
+function storedWalletCount(page) {
+    return page.storage.read("autistmask").wallets.length;
+}
+
+describe("Allow weak passwords", () => {
+    test("unticked: a password shorter than 12 characters is refused", async () => {
+        const page = await openAddWallet(false);
+        await importWith(page, "short");
+        expect(page.text(ERROR)).toBe(
+            "Password must be at least 12 characters.",
+        );
+        expect(storedWalletCount(page)).toBe(1);
+        expect(page.visibleViews()).toEqual(["add-wallet"]);
+    });
+
+    test("ticked: a password shorter than 12 characters is accepted", async () => {
+        const page = await openAddWallet(true);
+        await importWith(page, "short");
+        expect(page.text(ERROR)).toBe("");
+        expect(storedWalletCount(page)).toBe(2);
+        expect(page.visibleViews()).toEqual(["main"]);
+    });
+
+    test.each([false, true])(
+        "an empty password is refused (ticked: %s)",
+        async (allow) => {
+            const page = await openAddWallet(allow);
+            await importWith(page, "");
+            expect(page.text(ERROR)).toBe("Please choose a password.");
+            expect(storedWalletCount(page)).toBe(1);
+            expect(page.visibleViews()).toEqual(["add-wallet"]);
+        },
+    );
+});

tests/approvalAmount.test.js

@@ -84,6 +84,9 @@ function walletsHolding(token, decimals) {
 beforeEach(() => {
     state.trackedTokens = [];
     state.wallets = [];
+    // The approval screen reads the explorer's report only while "Use
+    // Blockscout" is on.
+    state.useBlockscout = true;
 });
 
 describe("resolveTokenDecimals", () => {

tests/approvalUseBlockscoutOff.test.js

@@ -0,0 +1,308 @@
+// While "Use Blockscout" is off, the approval screens, and the screens that
+// follow TxApproval, take a token's name and scale from the bundled list and
+// the tracked tokens alone (https://git.eeqj.de/sneak/AutistMask/issues/668).
+// A token missing from both gets a line under it. The line says Blockscout's
+// report of the user's balances is not used to name the token. While the
+// setting is on, Blockscout's report of the user's holding is a source too, as
+// before.
+//
+// Booted through the real popup entry point, as the approval window or as a
+// popup reopened onto SuccessTx, WaitTx or ErrorTx. The vault is mocked so that
+// no password has to be hashed: the stored secret decrypts to the test key
+// below.
+
+jest.mock("../src/shared/vault", () => ({
+    decryptWithPassword: jest.fn(),
+    encryptWithPassword: jest.fn(),
+}));
+
+const { Interface, Wallet } = require("ethers");
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+} = require("./support/popupBoot");
+
+// A published test key, never used for real funds.
+const SIGNER_KEY =
+    "0x59c6995e998f97a5a0044966f0945389dc9e86dae88c7a8412f4603b6b78690d";
+const signer = new Wallet(SIGNER_KEY);
+const ORIGIN = "https://dapp.example";
+const RECIPIENT = "0x2222222222222222222222222222222222222222";
+const TX_HASH = "0x" + "ab".repeat(32);
+// Outside the bundled list, and not tracked.
+const TOKEN = "0xE2E0000000000000000000000000000000000E2e";
+// In the bundled list, at 6 decimals.
+const USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
+
+const LINE =
+    'Blockscout\'s report of your balances is not used to name this token, because "Use Blockscout" is off in Settings.';
+
+// TOKEN as Blockscout reports the user's holding of it.
+const TOKEN_ROW = {
+    address: TOKEN,
+    name: "Novel",
+    symbol: "NOVEL",
+    decimals: "6",
+    balance: "5000.0",
+    holders: 5000,
+};
+
+// A transfer of 5,000 of a 6-decimal token to RECIPIENT.
+const TRANSFER_DATA = new Interface([
+    "function transfer(address to, uint256 amount)",
+]).encodeFunctionData("transfer", [RECIPIENT, 5000000000n]);
+
+// An EIP-2612 permit letting RECIPIENT take 5,000 of TOKEN.
+const PERMIT = {
+    types: {
+        EIP712Domain: [
+            { name: "name", type: "string" },
+            { name: "chainId", type: "uint256" },
+            { name: "verifyingContract", type: "address" },
+        ],
+        Permit: [
+            { name: "owner", type: "address" },
+            { name: "spender", type: "address" },
+            { name: "value", type: "uint256" },
+            { name: "nonce", type: "uint256" },
+            { name: "deadline", type: "uint256" },
+        ],
+    },
+    primaryType: "Permit",
+    domain: { name: "Novel", chainId: 1, verifyingContract: TOKEN },
+    message: {
+        owner: signer.address,
+        spender: RECIPIENT,
+        value: "5000000000",
+        nonce: "0",
+        deadline: "1790000000",
+    },
+};
+
+// The stored profile: the user's one address holds `tokenBalances`.
+function profile(useBlockscout, tokenBalances, extra) {
+    return unversionedValidProfile({
+        useBlockscout,
+        wallets: [
+            {
+                type: "key",
+                name: "Wallet 1",
+                encryptedSecret: "encrypted-key",
+                addresses: [
+                    {
+                        address: signer.address,
+                        balance: "1.0",
+                        tokenBalances,
+                    },
+                ],
+            },
+        ],
+        activeAddress: signer.address,
+        allowedSites: { [signer.address]: [ORIGIN] },
+        ...extra,
+    });
+}
+
+// The approval window for the site's request. The request is a transfer sent to
+// `token`, or a signature request when `signParams` is given. The background
+// answers the signed transaction with `txResponse`.
+function bootApproval(stored, { token = TOKEN, signParams, txResponse } = {}) {
+    return bootPopup(stored, {
+        search: "?approval=approval-1",
+        runtime: {
+            connect: () => ({ postMessage: () => {} }),
+            sendMessage: (msg, reply) => {
+                if (msg.type === "AUTISTMASK_GET_APPROVAL") {
+                    reply({
+                        type: signParams ? "sign" : "tx",
+                        origin: ORIGIN,
+                        isPhishingDomain: false,
+                        approvedFrom: signer.address,
+                        signParams,
+                        approvedTx: {
+                            type: 2,
+                            from: signer.address,
+                            chainId: "0x1",
+                            nonce: "0x7",
+                            gasLimit: "0x30d40",
+                            maxPriorityFeePerGas: "0x3b9aca00",
+                            maxFeePerGas: "0x77359400",
+                            to: token,
+                            value: "0x0",
+                            data: TRANSFER_DATA,
+                            accessList: [],
+                        },
+                    });
+                } else if (msg.type === "AUTISTMASK_TX_RESPONSE") {
+                    reply(txResponse);
+                } else {
+                    reply(undefined);
+                }
+            },
+        },
+    });
+}
+
+beforeEach(() => {
+    // The page logs its failed RPC reads; the stub node in popupBoot.js
+    // answers none.
+    jest.spyOn(console, "error").mockImplementation(() => {});
+});
+
+afterEach(() => {
+    cleanupPopup();
+    jest.restoreAllMocks();
+});
+
+describe("TxApproval", () => {
+    test("has the line under a token it cannot name while Use Blockscout is off", async () => {
+        const page = await bootApproval(profile(false, []));
+        const details = page.node("approve-tx-decoded-details").innerHTML;
+        expect(details).toContain("Unknown token");
+        expect(details).toContain(LINE);
+        expect(details).toContain("5000000000 base units (decimals unknown)");
+        cleanupPopup();
+
+        // The bundled list names USDC, so there is nothing to say.
+        const bundled = await bootApproval(profile(false, []), {
+            token: USDC,
+        });
+        expect(
+            bundled.node("approve-tx-decoded-details").innerHTML,
+        ).not.toContain(LINE);
+        cleanupPopup();
+
+        const on = await bootApproval(profile(true, [TOKEN_ROW]));
+        const named = on.node("approve-tx-decoded-details").innerHTML;
+        expect(named).toContain("5000.0000 NOVEL");
+        expect(named).not.toContain(LINE);
+    });
+
+    test("names nothing from a Blockscout entry still in the balances while Use Blockscout is off", async () => {
+        const page = await bootApproval(profile(false, [TOKEN_ROW]));
+        const details = page.node("approve-tx-decoded-details").innerHTML;
+        expect(details).not.toContain("NOVEL");
+        expect(details).toContain("Unknown token");
+        expect(details).toContain(LINE);
+    });
+
+    test.each([
+        ["WaitTx", { txHash: TX_HASH }, "wait-tx"],
+        [
+            "ErrorTx",
+            { error: "The transaction could not be sent.", retryable: false },
+            "error-tx",
+        ],
+    ])(
+        "%s after it says so under the amount while Use Blockscout is off",
+        async (_name, txResponse, view) => {
+            const page = await bootApproval(profile(false, []), {
+                txResponse,
+            });
+            const { decryptWithPassword } = require("../src/shared/vault");
+            decryptWithPassword.mockResolvedValue(SIGNER_KEY);
+            page.node("approve-tx-password").value = "any password";
+            await page.click("btn-approve-tx");
+            expect(page.visibleViews()).toEqual([view]);
+            expect(page.node(view + "-token-note").innerHTML).toBe(
+                `<div class="text-xs text-muted">${LINE}</div>`,
+            );
+        },
+    );
+});
+
+test("SuccessTx says so under the decoded token while Use Blockscout is off", async () => {
+    const page = await bootPopup(
+        profile(false, [], {
+            currentView: "success-tx",
+            viewStack: ["main"],
+            viewData: {
+                amount: "5000000000 base units (decimals unknown)",
+                symbol: "?",
+                to: RECIPIENT,
+                hash: TX_HASH,
+                blockNumber: 21000000,
+                chainId: "0x1",
+                decoded: {
+                    name: "Token Transfer",
+                    description: "Transfer ERC-20 token",
+                    details: [
+                        {
+                            label: "Token",
+                            value: TOKEN,
+                            address: TOKEN,
+                            isToken: true,
+                        },
+                    ],
+                },
+            },
+        }),
+    );
+    expect(page.visibleViews()).toEqual(["success-tx"]);
+    const decoded = page.node("success-tx-decoded").innerHTML;
+    expect(decoded).toContain("Unknown token");
+    expect(decoded).toContain(LINE);
+});
+
+test.each([
+    [
+        "wait-tx",
+        {
+            pendingWait: {
+                hash: TX_HASH,
+                txInfo: {
+                    to: RECIPIENT,
+                    amount: "1",
+                    token: 42,
+                    chainId: "0x1",
+                },
+                broadcastTime: Date.now(),
+            },
+        },
+    ],
+    [
+        "error-tx",
+        {
+            amount: "1",
+            symbol: "?",
+            token: 42,
+            to: RECIPIENT,
+            hash: TX_HASH,
+            message: "The transaction failed.",
+            chainId: "0x1",
+        },
+    ],
+])(
+    "a popup reopened onto %s shows no line for a stored token that is not text",
+    async (view, viewData) => {
+        const page = await bootPopup(
+            profile(false, [], {
+                currentView: view,
+                viewStack: ["main"],
+                viewData,
+            }),
+        );
+        expect(page.pageErrors).toEqual([]);
+        expect(page.visibleViews()).toEqual([view]);
+        expect(page.node(view + "-token-note").innerHTML).toBe("");
+    },
+);
+
+test("SignApproval says so under a permit's token while Use Blockscout is off", async () => {
+    const signParams = {
+        method: "eth_signTypedData_v4",
+        typedData: JSON.stringify(PERMIT),
+        from: signer.address,
+    };
+    const page = await bootApproval(profile(false, []), { signParams });
+    const message = page.node("approve-sign-message").innerHTML;
+    expect(message).toContain("Unknown token");
+    expect(message).toContain(LINE);
+    cleanupPopup();
+
+    const on = await bootApproval(profile(true, [TOKEN_ROW]), { signParams });
+    const named = on.node("approve-sign-message").innerHTML;
+    expect(named).toContain("5000.0000 NOVEL");
+    expect(named).not.toContain(LINE);
+});

tests/approvalWindow.test.js

@@ -12,6 +12,7 @@ const {
     cleanupPopup,
     settle,
     unversionedValidProfile,
+    ADDRESS,
 } = require("./support/popupBoot");
 
 afterEach(cleanupPopup);
@@ -174,3 +175,136 @@ test("a connection prompt in the toolbar popup leaves the browser window alone",
     expect(windows.updates).toEqual([]);
     expect(env.pageErrors).toEqual([]);
 });
+
+// Each row holds a transaction or signature approval as the background
+// describes it, plus the element ids of the screen that shows it. `refusal` is
+// the message the background refuses a Reject with.
+const TX_AND_SIGN_APPROVALS = [
+    {
+        kind: "transaction",
+        view: "approve-tx",
+        reject: "btn-reject-tx",
+        error: "approve-tx-error",
+        type: "AUTISTMASK_TX_RESPONSE",
+        refusal: "This transaction is already being sent.",
+        approval: {
+            type: "tx",
+            approvedFrom: ADDRESS,
+            approvedTx: {
+                chainId: 1,
+                to: ADDRESS,
+                value: "0",
+                data: "0x",
+                gasLimit: "21000",
+                maxFeePerGas: "1000000000",
+                maxPriorityFeePerGas: "1000000000",
+                nonce: 0,
+            },
+        },
+    },
+    {
+        kind: "signature",
+        view: "approve-sign",
+        reject: "btn-reject-sign",
+        error: "approve-sign-error",
+        type: "AUTISTMASK_SIGN_RESPONSE",
+        refusal: "This request is already being signed.",
+        approval: {
+            type: "sign",
+            approvedFrom: ADDRESS,
+            signParams: {
+                method: "personal_sign",
+                message: "0x48656c6c6f",
+                from: ADDRESS,
+            },
+        },
+    },
+];
+
+// A closed transaction or signature window leaves its request pending
+// (https://git.eeqj.de/sneak/AutistMask/issues/673). So Reject closes the
+// window only once the background has the rejection. A message sent as the
+// window closes can be lost, and the request would stay pending although the
+// user rejected it.
+test.each(TX_AND_SIGN_APPROVALS)(
+    "Reject on a $kind approval closes the window only once the background has answered",
+    async ({ view, reject, type, approval }) => {
+        let describeApproval = null;
+        let answerReject = null;
+        const sent = [];
+        const env = await bootPopup(unversionedValidProfile(), {
+            search: "?approval=approval-1",
+            runtime: {
+                connect: () => ({ postMessage: () => {} }),
+                sendMessage: (msg, reply) => {
+                    if (msg.type === "AUTISTMASK_GET_APPROVAL") {
+                        describeApproval = reply;
+                    }
+                    if (msg.type === type) {
+                        sent.push(msg);
+                        answerReject = reply;
+                    }
+                },
+            },
+        });
+        describeApproval({
+            ...approval,
+            origin: "https://dapp.example",
+            isPhishingDomain: false,
+        });
+        await settle();
+        expect(env.visibleViews()).toEqual([view]);
+        const close = jest.fn();
+        globalThis.window.close = close;
+
+        const clicked = env.click(reject);
+        await settle();
+        expect(sent).toEqual([{ type, id: "approval-1", approved: false }]);
+        expect(close).not.toHaveBeenCalled();
+
+        answerReject(null);
+        await clicked;
+        expect(close).toHaveBeenCalledTimes(1);
+        expect(env.pageErrors).toEqual([]);
+    },
+);
+
+// After Confirm or Sign, the background refuses a Reject while the transaction
+// is being sent or the signature checked. The request is not rejected then, so
+// the window stays open and shows the background's message.
+test.each(TX_AND_SIGN_APPROVALS)(
+    "Reject on a $kind approval that the background refuses shows the background's message and keeps the window open",
+    async ({ view, reject, error, type, refusal, approval }) => {
+        let describeApproval = null;
+        let answerReject = null;
+        const env = await bootPopup(unversionedValidProfile(), {
+            search: "?approval=approval-1",
+            runtime: {
+                connect: () => ({ postMessage: () => {} }),
+                sendMessage: (msg, reply) => {
+                    if (msg.type === "AUTISTMASK_GET_APPROVAL") {
+                        describeApproval = reply;
+                    }
+                    if (msg.type === type) answerReject = reply;
+                },
+            },
+        });
+        describeApproval({
+            ...approval,
+            origin: "https://dapp.example",
+            isPhishingDomain: false,
+        });
+        await settle();
+        const close = jest.fn();
+        globalThis.window.close = close;
+
+        const clicked = env.click(reject);
+        await settle();
+        answerReject({ error: refusal, retryable: false });
+        await clicked;
+        expect(close).not.toHaveBeenCalled();
+        expect(env.visibleViews()).toEqual([view]);
+        expect(env.text(error)).toBe(refusal);
+        expect(env.pageErrors).toEqual([]);
+    },
+);

tests/backgroundApproval.test.js

@@ -241,10 +241,11 @@ function loadBackground(options) {
     let connectListener = null;
     const created = [];
     const removed = [];
-    // Every URL the background put on the browser action. A site approval
+    // Every URL the background put on the browser action. When a test gives
-    // raised through action.openPopup() opens no window at all, so this is
+    // the URL the action holds before the worker starts, that URL comes
-    // the only place its id appears.
+    // first. A site approval raised through action.openPopup() opens no
-    const actionPopups = [];
+    // window at all, so this is the only place its id appears.
+    const actionPopups = opts.toolbarPopup ? [opts.toolbarPopup] : [];
     const openPopup = jest.fn(() => Promise.resolve());
 
     global.chrome = {
@@ -774,10 +775,9 @@ describe("one transaction approval at a time", () => {
 
     // The user closes an approval window that looks hung while the attempt
     // behind it is still running, and that attempt then fails in a way that
-    // would normally leave the approval standing for a retry. There is no
+    // leaves the approval standing for a retry. The toolbar popup opens it, so
-    // window left to retry in, so leaving it standing answers the requesting
+    // the user can still retry it, and answering it frees the slot.
-    // page never — and holds the slot for the life of the worker with it.
+    test("an approval whose window closed under a failed attempt is retried from the toolbar popup, and frees the next request", async () => {
-    test("an approval whose window closed under a failed attempt is answered, and frees the next request", async () => {
         const stalled = deferred();
         const bg = loadBackground();
 
@@ -808,11 +808,28 @@ describe("one transaction approval at a time", () => {
 
         stalled.resolve();
         await settle();
-        expect(first.result()).toEqual({
+        expect(first.result()).toBeNull();
-            error: { code: 4001, message: "User rejected the request." },
+        expect(bg.actionPopups[bg.actionPopups.length - 1]).toBe(
-        });
+            "src/popup/index.html?approval=" + first.id(),
+        );
 
         bg.setStateReadHook(null);
+        bg.broadcastTransaction.mockResolvedValue({ hash: "0xfeed" });
+        bg.send(
+            {
+                type: "AUTISTMASK_TX_RESPONSE",
+                id: first.id(),
+                approved: true,
+                rawSignedTx: await signedAtNonce(NONCE),
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        expect(first.result()).toEqual({ result: "0xfeed" });
+        expect(bg.actionPopups[bg.actionPopups.length - 1]).toBe(
+            "src/popup/index.html",
+        );
+
         const second = bg.requestTx();
         await settle();
         expect(second.result()).toBeNull();
@@ -853,8 +870,10 @@ describe("one transaction approval at a time", () => {
         const first = bg.requestTx();
         await settle();
 
-        // The user closes the approval window, which rejects it.
+        bg.send(
-        bg.closeWindow(1);
+            { type: "AUTISTMASK_TX_RESPONSE", id: first.id(), approved: false },
+            { url: bg.fromPopup.url },
+        );
         await settle();
         expect(first.result()).toEqual({
             error: { code: 4001, message: "User rejected the request." },
@@ -897,7 +916,7 @@ describe("the worker keeps running while an approval is pending", () => {
         try {
             const bg = loadBackground();
             const calls = global.chrome.runtime.getPlatformInfo;
-            bg.requestTx();
+            const pending = bg.requestTx();
             await settle();
             expect(startTimer).toHaveBeenCalledTimes(1);
             expect(startTimer.mock.calls[0][1]).toBe(20000);
@@ -906,11 +925,23 @@ describe("the worker keeps running while an approval is pending", () => {
             tick();
             expect(calls).toHaveBeenCalledTimes(1);
 
-            // The user closes the approval window, which rejects it.
+            // A closed window leaves the approval pending, so the calls go on.
             bg.closeWindow(1);
             await settle();
             tick();
-            expect(calls).toHaveBeenCalledTimes(1);
+            expect(calls).toHaveBeenCalledTimes(2);
+
+            bg.send(
+                {
+                    type: "AUTISTMASK_TX_RESPONSE",
+                    id: pending.id(),
+                    approved: false,
+                },
+                { url: bg.fromPopup.url },
+            );
+            await settle();
+            tick();
+            expect(calls).toHaveBeenCalledTimes(2);
             expect(stopTimer).toHaveBeenCalledWith(1);
         } finally {
             startTimer.mockRestore();
@@ -1841,6 +1872,237 @@ describe("the interlock releases a failed attempt", () => {
     });
 });
 
+// A transaction or signature approval stays pending when its window closes.
+// The browser can close that window when the user clicks away from it, for
+// example to copy the password from a password manager. The toolbar popup then
+// opens the approval, and the user answers it there
+// (https://git.eeqj.de/sneak/AutistMask/issues/673).
+describe("a closed approval window leaves the request pending", () => {
+    // The URL the toolbar popup opens now.
+    function toolbarPopup(bg) {
+        return bg.actionPopups[bg.actionPopups.length - 1];
+    }
+
+    // The timer that keeps the worker running while an approval is pending is
+    // stubbed, so no test here leaves that timer running when it ends.
+    let keepRunningTimer;
+    beforeEach(() => {
+        keepRunningTimer = jest
+            .spyOn(global, "setInterval")
+            .mockImplementation(() => 1);
+    });
+    afterEach(() => {
+        keepRunningTimer.mockRestore();
+    });
+
+    test("the toolbar popup opens a closed transaction approval, and approving it there sends", async () => {
+        const bg = loadBackground();
+        const pending = bg.requestTx();
+        await settle();
+
+        bg.closeWindow(1);
+        await settle();
+        expect(pending.result()).toBeNull();
+        expect(toolbarPopup(bg)).toBe(
+            "src/popup/index.html?approval=" + pending.id(),
+        );
+
+        bg.broadcastTransaction.mockResolvedValue({ hash: "0xfeed" });
+        bg.send(
+            {
+                type: "AUTISTMASK_TX_RESPONSE",
+                id: pending.id(),
+                approved: true,
+                rawSignedTx: await signedAtNonce(NONCE),
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        expect(pending.result()).toEqual({ result: "0xfeed" });
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+    });
+
+    test("Reject in the toolbar popup answers 4001, and the toolbar popup opens the wallet again", async () => {
+        const bg = loadBackground();
+        const pending = bg.requestSign();
+        await settle();
+
+        bg.closeWindow(1);
+        await settle();
+        expect(pending.result()).toBeNull();
+        expect(toolbarPopup(bg)).toBe(
+            "src/popup/index.html?approval=" + pending.id(),
+        );
+
+        const reject = bg.send(
+            {
+                type: "AUTISTMASK_SIGN_RESPONSE",
+                id: pending.id(),
+                approved: false,
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        expect(pending.result()).toEqual({
+            error: { code: 4001, message: "User rejected the request." },
+        });
+        // The popup closes its window only once this answer arrives.
+        expect(reject.sendResponse).toHaveBeenCalledWith(null);
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+    });
+
+    test("with two closed, the toolbar popup opens the older one first, then the other", async () => {
+        const bg = loadBackground();
+        const sign = bg.requestSign();
+        await settle();
+        const signId = sign.id();
+        const tx = bg.requestTx();
+        await settle();
+
+        // The signature request is in window 1 and the transaction in window
+        // 2. The newer window is closed first.
+        bg.closeWindow(2);
+        bg.closeWindow(1);
+        await settle();
+        expect(toolbarPopup(bg)).toBe(
+            "src/popup/index.html?approval=" + signId,
+        );
+
+        bg.send(
+            { type: "AUTISTMASK_SIGN_RESPONSE", id: signId, approved: false },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        expect(toolbarPopup(bg)).toBe(
+            "src/popup/index.html?approval=" + tx.id(),
+        );
+
+        const reject = bg.send(
+            { type: "AUTISTMASK_TX_RESPONSE", id: tx.id(), approved: false },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        expect(tx.result()).toEqual({
+            error: { code: 4001, message: "User rejected the request." },
+        });
+        expect(reject.sendResponse).toHaveBeenCalledWith(null);
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+    });
+
+    // The user can close the window while the attempt after Confirm runs. That
+    // attempt answers the request, so meanwhile the toolbar popup opens the
+    // wallet. Opened from the toolbar, the approval would look unanswered.
+    test("when the window closes during an attempt that sends, the toolbar popup keeps opening the wallet", async () => {
+        const bg = loadBackground();
+        const pending = bg.requestTx();
+        await settle();
+
+        const inFlight = deferred();
+        bg.broadcastTransaction.mockReturnValue(inFlight.promise);
+        bg.send(
+            {
+                type: "AUTISTMASK_TX_RESPONSE",
+                id: pending.id(),
+                approved: true,
+                rawSignedTx: await signedAtNonce(NONCE),
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        bg.closeWindow(1);
+        await settle();
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+
+        inFlight.resolve({ hash: "0xfeed" });
+        await settle();
+        expect(pending.result()).toEqual({ result: "0xfeed" });
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+    });
+
+    test("when the window closes during an attempt that fails retryably, the toolbar popup opens the wallet until the attempt ends, then the approval", async () => {
+        const stalled = deferred();
+        const bg = loadBackground();
+        const pending = bg.requestTx();
+        await settle();
+
+        bg.setStateReadHook(async () => {
+            await stalled.promise;
+            throw new Error("The wallet data could not be read.");
+        });
+        bg.send(
+            {
+                type: "AUTISTMASK_TX_RESPONSE",
+                id: pending.id(),
+                approved: true,
+                rawSignedTx: await signedAtNonce(NONCE),
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        bg.closeWindow(1);
+        await settle();
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+
+        stalled.resolve();
+        await settle();
+        expect(pending.result()).toBeNull();
+        expect(toolbarPopup(bg)).toBe(
+            "src/popup/index.html?approval=" + pending.id(),
+        );
+
+        // A retry from the toolbar popup holds the approval again, so the
+        // toolbar popup opens the wallet while that retry runs.
+        bg.setStateReadHook(null);
+        const inFlight = deferred();
+        bg.broadcastTransaction.mockReturnValue(inFlight.promise);
+        bg.send(
+            {
+                type: "AUTISTMASK_TX_RESPONSE",
+                id: pending.id(),
+                approved: true,
+                rawSignedTx: await signedAtNonce(NONCE),
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+
+        inFlight.resolve({ hash: "0xfeed" });
+        await settle();
+        expect(pending.result()).toEqual({ result: "0xfeed" });
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+    });
+
+    test("an address switch still rejects a closed approval", async () => {
+        const bg = loadBackground();
+        const pending = bg.requestTx();
+        await settle();
+        bg.closeWindow(1);
+        await settle();
+        expect(pending.result()).toBeNull();
+
+        bg.send(
+            { type: "AUTISTMASK_ACTIVE_CHANGED" },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        expect(pending.result()).toEqual({
+            error: { code: 4001, message: "User rejected the request." },
+        });
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+    });
+
+    // The worker can stop while an approval waits with its window closed. The
+    // approval is lost with the worker, but the toolbar popup keeps its URL.
+    // The next worker points the toolbar popup back at the wallet.
+    test("a worker that starts points the toolbar popup back at the wallet", () => {
+        const bg = loadBackground({
+            toolbarPopup: "src/popup/index.html?approval=lost-approval",
+        });
+        expect(toolbarPopup(bg)).toBe("src/popup/index.html");
+    });
+});
+
 // The claim is what makes one approval one broadcast, so it has to hold
 // against everything else that retires an approval, not just against a second
 // AUTISTMASK_TX_RESPONSE. Each of these paths used to resolve the waiting
@@ -1961,20 +2223,6 @@ describe("a claimed approval outlives every other retirement path", () => {
     });
 
     // The refusals above must not cost the rejection its ordinary meaning.
-    test("with no attempt running, closing the window still rejects", async () => {
-        const bg = loadBackground();
-        const pending = bg.requestTx();
-        await settle();
-
-        bg.closeWindow(1);
-        await settle();
-
-        expect(pending.result()).toEqual({
-            error: { code: 4001, message: "User rejected the request." },
-        });
-        expect(bg.broadcastTransaction).not.toHaveBeenCalled();
-    });
-
     test("with no attempt running, an active-address switch still rejects and closes", async () => {
         const bg = loadBackground();
         const pending = bg.requestTx();
@@ -2584,15 +2832,12 @@ describe("a site connection decided as the popup closes", () => {
         });
     });
 
-    // The `isSite &&` half of that skip, which is what keeps it from reaching
+    // That skip must not reach a tx or sign approval. The popup connects its
-    // a tx or sign approval. The popup connects its port in show() before it
+    // port in show() before it knows the approval's type, and the background
-    // knows the approval's type, and the background sets portConnected without
+    // sets portConnected without looking at the type either, so a tx approval
-    // looking at the type either, so a tx approval in the fallback window
+    // carries the flag too. If the window event skipped it, windowClosed would
-    // carries the flag too. Without the conjunct the window event would skip
+    // never be set, and the toolbar popup would never open the approval.
-    // it, windowClosed would never be set, releaseApproval() would never settle
+    test("a tx window closed with the port connected is still opened by the toolbar popup", async () => {
-    // it, and the page would hang — the #271 regression this guard is written
-    // around.
-    test("a tx window closed with the port connected still rejects", async () => {
         const bg = loadBackground();
         const pending = bg.requestTx();
         await settle();
@@ -2600,9 +2845,10 @@ describe("a site connection decided as the popup closes", () => {
         await settle();
         bg.closeWindow(1);
         await settle();
-        expect(pending.result()).toEqual({
+        expect(pending.result()).toBeNull();
-            error: { code: 4001, message: "User rejected the request." },
+        expect(bg.actionPopups[bg.actionPopups.length - 1]).toBe(
-        });
+            "src/popup/index.html?approval=" + pending.id(),
+        );
     });
 });
 
@@ -2994,13 +3240,14 @@ describe("where an approval window opens", () => {
         expect(bg.created[1].left).toBeUndefined();
         expect(bg.created[1].top).toBeUndefined();
 
-        // The request waits on the second window rather than failing:
+        // The request waits on the second window rather than failing. Once
-        // closing that window is refusing the prompt.
+        // that window closes, the toolbar popup opens the request.
         expect(sign.result()).toBeNull();
         bg.closeWindow(2);
         await settle();
-        expect(sign.result()).toEqual({
+        expect(sign.result()).toBeNull();
-            error: { code: 4001, message: "User rejected the request." },
+        expect(bg.actionPopups[bg.actionPopups.length - 1]).toBe(
-        });
+            "src/popup/index.html?approval=" + sign.id(),
+        );
     });
 });

tests/backgroundStateIsolation.test.js

@@ -142,6 +142,8 @@ function loadWorker(networkId, opts) {
         },
         refreshBalances:
             options.refreshBalances || jest.fn(async () => undefined),
+        dropUntrackedTokens: jest.requireActual("../src/shared/balances")
+            .dropUntrackedTokens,
     }));
     jest.doMock("../src/shared/phishingDomains", () => ({
         isPhishingDomain: () => false,
@@ -443,3 +445,54 @@ describe("a balance refresh under a network switch", () => {
         );
     });
 });
+
+describe("a balance refresh under a change of Use Blockscout", () => {
+    // Turning "Use Blockscout" off drops the tokens the user has not tracked
+    // (src/popup/views/settings.js). Blockscout may have answered a refresh
+    // just before. That refresh still saves its balances when it returns, but
+    // not those tokens. The same refresh in the popup is in
+    // tests/blockscoutEtherscanSettings.test.js.
+    test("a refresh that returns after Use Blockscout was turned off saves its balances without the untracked token", async () => {
+        const roundTrip = deferred();
+        const started = deferred();
+
+        const bg = loadWorker("mainnet", {
+            refreshBalances: async (wallets) => {
+                started.resolve();
+                await roundTrip.promise;
+                wallets[0].addresses[0].balance = "7.0";
+                wallets[0].addresses[0].tokenBalances = [
+                    {
+                        address: "0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+                        name: "Test Token",
+                        symbol: "TST",
+                        decimals: 18,
+                        balance: "5.0",
+                        holders: 50000,
+                    },
+                ];
+            },
+        });
+        global.chrome.storage.write("autistmask", {
+            ...bg.persisted(),
+            useBlockscout: true,
+        });
+
+        const refresh = bg.fireBalanceAlarm();
+        await started.promise;
+
+        // The user unticks "Use Blockscout" in Settings while the round trip
+        // is out.
+        global.chrome.storage.write("autistmask", {
+            ...bg.persisted(),
+            useBlockscout: false,
+        });
+
+        roundTrip.resolve();
+        await refresh;
+
+        const after = bg.persisted();
+        expect(after.wallets[0].addresses[0].balance).toBe("7.0");
+        expect(after.wallets[0].addresses[0].tokenBalances).toEqual([]);
+    });
+});

tests/balanceRefreshCancelled.test.js

@@ -18,6 +18,17 @@ const {
 const RPC_URL = "https://rpc.example.invalid";
 const EXPLORER_URL = "https://explorer.example.invalid/api/v2";
 const ADDRESS = "0x1111111111111111111111111111111111111111";
+const TRACKED = {
+    address: "0x7777777777777777777777777777777777777777",
+    symbol: "TRK",
+    decimals: 6,
+};
+
+// Blockscout is asked only while the stored "Use Blockscout" is on.
+const { makeStorageStub } = require("./support/storageStub");
+globalThis.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+};
 
 const realFetch = globalThis.fetch;
 let logged;
@@ -30,9 +41,9 @@ beforeEach(() => {
     const failedToFetch = async () => {
         throw new TypeError("Failed to fetch");
     };
-    // The RPC calls (ETH balance, ENS name, and the scan's balance and
+    // The RPC calls (ETH balance, ENS name, the tracked token's balance, and
-    // transaction count) and the explorer request (token balances) all fail
+    // the scan's balance and transaction count) and the explorer request (the
-    // the same way.
+    // other token balances) all fail the same way.
     FetchRequest.registerGetUrl(failedToFetch);
     globalThis.fetch = jest.fn(failedToFetch);
 });
@@ -49,7 +60,7 @@ function refresh(signal) {
         wallets,
         RPC_URL,
         EXPLORER_URL,
-        [],
+        [TRACKED],
         "mainnet",
         signal,
     );
@@ -60,6 +71,7 @@ test("a failure while the popup is open is reported", async () => {
     for (const label of [
         "ETH balance failed",
         "ENS reverse failed",
+        "token balance failed",
         "fetchTokenBalances failed: Failed to fetch",
     ]) {
         expect(logged.some((line) => line.includes(label))).toBe(true);

tests/balanceRefreshNetworkSwitch.test.js

@@ -97,9 +97,9 @@ test("a refresh that returns after a switch in Settings writes nothing, and the
     );
 });
 
-// The stored record still holds Ethereum Mainnet while the refresh's save reads
+// The switch is made only once the refresh's save, holding the lock, has
-// it, so only this page's own network shows the switch.
+// written Ethereum Mainnet's balances, and the switch then clears them.
-test("a refresh whose save is reading the stored record when the user switches in Settings writes nothing", async () => {
+test("a refresh whose save is reading the stored record when the user switches in Settings leaves none of its balances stored", async () => {
     const page = await bootPopup(unversionedValidProfile());
     expect(page.pageErrors).toEqual([]);
     const { state } = require("../src/shared/state");
@@ -145,7 +145,8 @@ test("a refresh that returns after the background switched the network writes no
 
     const refresh = await holdRefresh(page);
     // The background writes the switch to Sepolia, as its updateState() does
-    // once the user approves a site's request. This page is not told.
+    // once the user approves a site's request. This page is not told of it
+    // yet.
     const record = page.storage.read("autistmask");
     applyChainSwitchFields(record, "sepolia");
     page.storage.write("autistmask", record);

tests/blockscoutEtherscanSettings.test.js

@@ -0,0 +1,848 @@
+// Blockscout and Etherscan are sent none of the user's data until the user
+// turns on a setting for each
+// (https://git.eeqj.de/sneak/AutistMask/issues/668). A new profile has "Use
+// Blockscout" and "Check recipients on Etherscan" both off. While a setting is
+// off, no request sends its service the user's data.
+//
+// One request still reaches Blockscout while "Use Blockscout" is off: the check
+// behind "Save" beside the Blockscout URL in Settings. That check asks the URL
+// only for `/stats` and sends none of the user's data.
+//
+// Before any other request to Blockscout or Etherscan, the wallet reads that
+// service's setting from storage, not the page's copy. The wallet reads the
+// setting again when the answer lands. So a change saved by another page
+// applies at once. An open page also takes such a change and draws its screens
+// again.
+//
+// Only Blockscout reports the tokens the user has not tracked. While "Use
+// Blockscout" is off, no address keeps them and no screen lists them.
+//
+// The functions that make the requests are driven directly, against a fetch()
+// that records every URL it is asked for. The screens are driven through the
+// real popup over a stored profile (tests/support/popupBoot.js). The fetch()
+// stub in popupBoot.js records the same way.
+
+"use strict";
+
+const { FetchRequest } = require("ethers");
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    ADDRESS,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
+const { makeStorageStub } = require("./support/storageStub");
+const {
+    DEFAULT_STATE,
+    normalizePersisted,
+} = require("../src/shared/persistedState");
+const {
+    fetchTokenBalances,
+    refreshBalances,
+} = require("../src/shared/balances");
+const { fetchRecentTransactions } = require("../src/shared/transactions");
+const { getFullWarnings } = require("../src/shared/addressWarnings");
+const { checkEtherscanLabel } = require("../src/shared/etherscanLabels");
+const { HISTORY_OFF_TEXT, escapeHtml } = require("../src/popup/views/helpers");
+
+const RPC_URL = "https://rpc.example.invalid";
+const BLOCKSCOUT = "https://eth.blockscout.com/api/v2";
+const RECIPIENT = "0x2222222222222222222222222222222222222222";
+const TX_HASH = "0x" + "ab".repeat(32);
+const ZERO_WORD = "0x" + "0".repeat(64);
+
+// USDC, from the bundled list, as Blockscout reports a holding of it.
+const USDC_ROW = {
+    value: "5000000",
+    token: {
+        type: "ERC-20",
+        address_hash: "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
+        symbol: "USDC",
+        name: "USD Coin",
+        decimals: "6",
+        holders_count: "50000",
+    },
+};
+
+// A transfer of 1 ETH from RECIPIENT to ADDRESS, as Blockscout lists it in
+// ADDRESS's history.
+const HISTORY_ITEM = {
+    hash: TX_HASH,
+    block_number: 21000000,
+    timestamp: "2026-02-27T12:00:00.000Z",
+    from: { hash: RECIPIENT },
+    to: { hash: ADDRESS, is_contract: false },
+    value: "1000000000000000000",
+    method: null,
+    status: "ok",
+};
+
+// Etherscan's page for RECIPIENT, which labels it a phishing address.
+const PHISHING_PAGE =
+    "<html><head><title>Fake_Phishing1 | Address: " +
+    RECIPIENT +
+    " | Etherscan</title></head><body></body></html>";
+
+const realFetch = globalThis.fetch;
+
+afterEach(() => {
+    cleanupPopup();
+    jest.restoreAllMocks();
+});
+
+describe("a new profile", () => {
+    test("has both settings off", () => {
+        expect(DEFAULT_STATE.useBlockscout).toBe(false);
+        expect(DEFAULT_STATE.checkRecipientsOnEtherscan).toBe(false);
+        const loaded = normalizePersisted(undefined);
+        expect(loaded.useBlockscout).toBe(false);
+        expect(loaded.checkRecipientsOnEtherscan).toBe(false);
+    });
+
+    test("keeps either setting the user turned on", () => {
+        const loaded = normalizePersisted({
+            useBlockscout: true,
+            checkRecipientsOnEtherscan: true,
+        });
+        expect(loaded.useBlockscout).toBe(true);
+        expect(loaded.checkRecipientsOnEtherscan).toBe(true);
+    });
+});
+
+describe("where each request is made", () => {
+    // Every URL that fetch() was asked for, in order.
+    let asked;
+
+    // What Blockscout and Etherscan answer: USDC among ADDRESS's tokens,
+    // HISTORY_ITEM in its history, and PHISHING_PAGE for RECIPIENT.
+    function answer(url) {
+        return {
+            ok: true,
+            status: 200,
+            json: async () => {
+                if (url.endsWith("/token-balances")) return [USDC_ROW];
+                if (url.endsWith("/transactions")) {
+                    return { items: [HISTORY_ITEM] };
+                }
+                return { items: [] };
+            },
+            text: async () => PHISHING_PAGE,
+        };
+    }
+
+    async function recordAndAnswer(url) {
+        asked.push(String(url));
+        return answer(String(url));
+    }
+
+    beforeEach(() => {
+        asked = [];
+        globalThis.fetch = jest.fn(recordAndAnswer);
+    });
+
+    afterEach(() => {
+        globalThis.fetch = realFetch;
+        delete globalThis.chrome;
+    });
+
+    // Storage holds `profile` as the stored profile, or nothing when it is
+    // undefined.
+    function storing(profile) {
+        globalThis.chrome = {
+            storage: makeStorageStub(
+                profile === undefined ? {} : { autistmask: profile },
+            ),
+        };
+    }
+
+    test("Blockscout's token balances are asked for only while Use Blockscout is on", async () => {
+        storing({ useBlockscout: false });
+        expect(await fetchTokenBalances(ADDRESS, BLOCKSCOUT, [])).toEqual([]);
+        expect(asked).toEqual([]);
+
+        storing({ useBlockscout: true });
+        const rows = await fetchTokenBalances(ADDRESS, BLOCKSCOUT, []);
+        expect(rows.map((row) => row.symbol)).toEqual(["USDC"]);
+        expect(asked).toEqual([
+            BLOCKSCOUT + "/addresses/" + ADDRESS + "/token-balances",
+        ]);
+    });
+
+    test("the transaction history is asked for only while Use Blockscout is on", async () => {
+        storing({ useBlockscout: false });
+        expect(
+            await fetchRecentTransactions(ADDRESS, BLOCKSCOUT, "0x1"),
+        ).toEqual([]);
+        expect(asked).toEqual([]);
+
+        storing({ useBlockscout: true });
+        await fetchRecentTransactions(ADDRESS, BLOCKSCOUT, "0x1");
+        expect(asked.sort()).toEqual([
+            BLOCKSCOUT +
+                "/addresses/" +
+                ADDRESS +
+                "/token-transfers?type=ERC-20",
+            BLOCKSCOUT + "/addresses/" + ADDRESS + "/transactions",
+        ]);
+    });
+
+    test("the Etherscan label check is made only while the stored profile has Check recipients on Etherscan on", async () => {
+        const provider = {
+            getCode: async () => "0x",
+            getTransactionCount: async () => 1,
+            getBalance: async () => 0n,
+        };
+        const checkWith = async (profile) => {
+            storing(profile);
+            await getFullWarnings(RECIPIENT, provider, { chainId: "0x1" });
+        };
+
+        await checkWith(undefined);
+        await checkWith({ checkRecipientsOnEtherscan: false });
+        // Only a stored true is on, as when the profile is loaded.
+        await checkWith({ checkRecipientsOnEtherscan: "true" });
+        await checkWith({ checkRecipientsOnEtherscan: 42 });
+        expect(asked).toEqual([]);
+
+        await checkWith({ checkRecipientsOnEtherscan: true });
+        expect(asked).toEqual(["https://etherscan.io/address/" + RECIPIENT]);
+    });
+
+    // Asks with `setting` on in storage. Once every request is out, storage
+    // holds `after` for the setting, as when the user changes it here or on
+    // another page. Only then does each request get its answer.
+    async function answeredAfter(setting, after, ask) {
+        storing({ [setting]: true });
+        let release;
+        const held = new Promise((resolve) => {
+            release = resolve;
+        });
+        let requested;
+        const out = new Promise((resolve) => {
+            requested = resolve;
+        });
+        globalThis.fetch = jest.fn(async (url) => {
+            requested();
+            await held;
+            return recordAndAnswer(url);
+        });
+        const result = ask();
+        await out;
+        globalThis.chrome.storage.write("autistmask", { [setting]: after });
+        release();
+        return result;
+    }
+
+    // One row per request, giving:
+    //
+    //   - its name
+    //   - the setting that gates it
+    //   - how to make it
+    //   - its answer while that setting is off
+    test.each([
+        [
+            "Blockscout's token balances",
+            "useBlockscout",
+            () => fetchTokenBalances(ADDRESS, BLOCKSCOUT, []),
+            [],
+        ],
+        [
+            "the transaction history",
+            "useBlockscout",
+            () => fetchRecentTransactions(ADDRESS, BLOCKSCOUT, "0x1"),
+            [],
+        ],
+        [
+            "the Etherscan label check",
+            "checkRecipientsOnEtherscan",
+            () => checkEtherscanLabel(RECIPIENT, "0x1"),
+            null,
+        ],
+    ])(
+        "%s keeps an answer that lands while its setting is on, and drops one that lands after it went off",
+        async (_what, setting, ask, dropped) => {
+            expect(await answeredAfter(setting, true, ask)).not.toEqual(
+                dropped,
+            );
+            expect(await answeredAfter(setting, false, ask)).toEqual(dropped);
+        },
+    );
+
+    describe("a balance refresh", () => {
+        // The RPC endpoint answers every balance with zero. The ENS reverse
+        // lookup makes the only other calls, and it finds no resolver.
+        beforeEach(() => {
+            FetchRequest.registerGetUrl(async (req) => {
+                const body = JSON.parse(Buffer.from(req.body).toString("utf8"));
+                const reply = (r) => ({
+                    jsonrpc: "2.0",
+                    id: r.id,
+                    result: r.method === "eth_getBalance" ? "0x0" : ZERO_WORD,
+                });
+                const answer = Array.isArray(body)
+                    ? body.map(reply)
+                    : reply(body);
+                return {
+                    statusCode: 200,
+                    statusMessage: "OK",
+                    headers: { "content-type": "application/json" },
+                    body: Buffer.from(JSON.stringify(answer)),
+                };
+            });
+        });
+
+        afterEach(() => {
+            FetchRequest.registerGetUrl(FetchRequest.createGetUrlFunc());
+        });
+
+        // An address refreshed while "Use Blockscout" was on. It holds the USDC
+        // that Blockscout reported then.
+        function addressWithUsdc() {
+            return {
+                address: ADDRESS,
+                tokenBalances: [
+                    {
+                        address: USDC_ROW.token.address_hash,
+                        name: "USD Coin",
+                        symbol: "USDC",
+                        decimals: 6,
+                        balance: "5.0",
+                        holders: 50000,
+                    },
+                ],
+            };
+        }
+
+        async function refresh(addr, useBlockscout) {
+            storing({ useBlockscout });
+            await refreshBalances(
+                [{ addresses: [addr] }],
+                RPC_URL,
+                BLOCKSCOUT,
+                [],
+                "mainnet",
+            );
+        }
+
+        test("asks Blockscout nothing while Use Blockscout is off, and then lists no token the user has not tracked", async () => {
+            const addr = addressWithUsdc();
+            await refresh(addr, false);
+            expect(asked).toEqual([]);
+            expect(addr.tokenBalances).toEqual([]);
+        });
+
+        test("asks Blockscout for the token balances while Use Blockscout is on", async () => {
+            const addr = addressWithUsdc();
+            await refresh(addr, true);
+            expect(asked).toEqual([
+                BLOCKSCOUT + "/addresses/" + ADDRESS + "/token-balances",
+            ]);
+            expect(addr.tokenBalances.map((row) => row.symbol)).toEqual([
+                "USDC",
+            ]);
+        });
+    });
+});
+
+describe("the popup", () => {
+    // Every URL the booted page handed to fetch().
+    function fetched() {
+        return globalThis.fetch.mock.calls.map((call) => String(call[0]));
+    }
+
+    function blockscoutOrEtherscan(url) {
+        return url.includes("blockscout") || url.includes("etherscan");
+    }
+
+    beforeEach(() => {
+        // The screens below log their failed RPC reads; the stub node in
+        // popupBoot.js answers none.
+        jest.spyOn(console, "error").mockImplementation(() => {});
+    });
+
+    test("Home says why there is no history and only tracked tokens while Use Blockscout is off", async () => {
+        const page = await bootPopup(unversionedValidProfile());
+        expect(page.node("home-tx-list").innerHTML).toContain(
+            escapeHtml(HISTORY_OFF_TEXT),
+        );
+        expect(page.hidden("home-tokens-note")).toBe(false);
+        cleanupPopup();
+
+        const on = await bootPopup(
+            unversionedValidProfile({ useBlockscout: true }),
+        );
+        expect(on.node("home-tx-list").innerHTML).toContain(
+            "No transactions found.",
+        );
+        expect(on.hidden("home-tokens-note")).toBe(true);
+    });
+
+    // The transaction screen, as a reopened popup draws it.
+    function onTransactionScreen(extra) {
+        return unversionedValidProfile({
+            currentView: "transaction",
+            viewStack: ["main"],
+            selectedWallet: 0,
+            selectedAddress: 0,
+            viewData: {
+                tx: {
+                    hash: TX_HASH,
+                    from: ADDRESS,
+                    to: RECIPIENT,
+                    value: "1.0000",
+                    exactValue: "1.0",
+                    symbol: "ETH",
+                    timestamp: 1790000000,
+                    isError: false,
+                    direction: "sent",
+                    directionLabel: "Sent",
+                    contractAddress: null,
+                    chainId: "0x1",
+                },
+            },
+            ...extra,
+        });
+    }
+
+    test("TransactionDetail asks Blockscout for the transaction only while Use Blockscout is on", async () => {
+        const page = await bootPopup(onTransactionScreen());
+        expect(page.visibleViews()).toEqual(["transaction"]);
+        expect(fetched().filter(blockscoutOrEtherscan)).toEqual([]);
+        expect(page.hidden("tx-detail-blockscout-note")).toBe(false);
+        cleanupPopup();
+
+        const on = await bootPopup(
+            onTransactionScreen({ useBlockscout: true }),
+        );
+        expect(fetched().filter(blockscoutOrEtherscan)).toEqual([
+            BLOCKSCOUT + "/transactions/" + TX_HASH,
+        ]);
+        expect(on.hidden("tx-detail-blockscout-note")).toBe(true);
+    });
+
+    // Another page turns "Use Blockscout" off while TransactionDetail's request
+    // to Blockscout is out. This page draws TransactionDetail again with its
+    // line, and only then does Blockscout answer.
+    test("TransactionDetail shows nothing from an answer that lands after another page turned Use Blockscout off", async () => {
+        const page = await bootPopup(
+            onTransactionScreen({ useBlockscout: true }),
+        );
+        let release;
+        const held = new Promise((resolve) => {
+            release = resolve;
+        });
+        globalThis.fetch = jest.fn(async () => {
+            await held;
+            return {
+                ok: true,
+                status: 200,
+                json: async () => ({
+                    block_number: 21000000,
+                    fee: { value: "21000000000000" },
+                    raw_input: "0x12345678",
+                    method: "doSomething",
+                }),
+            };
+        });
+        require("../src/popup/views/transactionDetail").render();
+        await page.settle();
+        expect(fetched()).toEqual([BLOCKSCOUT + "/transactions/" + TX_HASH]);
+
+        await anotherPageAnnounces(page, { useBlockscout: false });
+        release();
+        await page.settle();
+
+        expect(page.visibleViews()).toEqual(["transaction"]);
+        expect(page.hidden("tx-detail-blockscout-note")).toBe(false);
+        for (const id of [
+            "tx-detail-block-section",
+            "tx-detail-network-section",
+            "tx-detail-calldata-section",
+            "tx-detail-rawdata-section",
+        ]) {
+            expect(page.hidden(id)).toBe(true);
+        }
+        expect(fetched()).toHaveLength(1);
+    });
+
+    // The confirmation screen for a send of 0.1 ETH to RECIPIENT, as a
+    // reopened popup draws it.
+    function onConfirmScreen(extra) {
+        return unversionedValidProfile({
+            currentView: "confirm-tx",
+            viewStack: ["main"],
+            selectedWallet: 0,
+            selectedAddress: 0,
+            viewData: {
+                pendingTx: {
+                    token: "ETH",
+                    from: ADDRESS,
+                    to: RECIPIENT,
+                    amount: "0.1",
+                    chainId: "0x1",
+                },
+            },
+            ...extra,
+        });
+    }
+
+    test("ConfirmTx asks Etherscan about the recipient only while Check recipients on Etherscan is on", async () => {
+        const page = await bootPopup(onConfirmScreen());
+        expect(page.visibleViews()).toEqual(["confirm-tx"]);
+        expect(fetched().filter(blockscoutOrEtherscan)).toEqual([]);
+        expect(page.hidden("confirm-etherscan-note")).toBe(false);
+        expect(page.hidden("confirm-etherscan-warning")).toBe(true);
+        cleanupPopup();
+
+        const on = await bootPopup(
+            onConfirmScreen({ checkRecipientsOnEtherscan: true }),
+        );
+        expect(fetched().filter(blockscoutOrEtherscan)).toEqual([
+            "https://etherscan.io/address/" + RECIPIENT,
+        ]);
+        expect(on.hidden("confirm-etherscan-note")).toBe(true);
+        expect(on.hidden("confirm-etherscan-warning")).toBe(false);
+    });
+
+    // Ticks or unticks a checkbox on the page, as the user does.
+    async function setBox(page, id, checked) {
+        const box = page.node(id);
+        box.checked = checked;
+        for (const fn of box.listeners.change) await fn();
+        await page.settle();
+    }
+
+    test("Welcome offers both settings unticked, and ticking one there stores it", async () => {
+        const page = await bootPopup(undefined);
+        expect(page.visibleViews()).toEqual(["welcome"]);
+        expect(page.node("welcome-use-blockscout").checked).toBe(false);
+        expect(page.node("welcome-check-recipients-on-etherscan").checked).toBe(
+            false,
+        );
+
+        await setBox(page, "welcome-use-blockscout", true);
+        expect(page.storage.read("autistmask").useBlockscout).toBe(true);
+        await setBox(page, "welcome-check-recipients-on-etherscan", true);
+        expect(page.storage.read("autistmask").checkRecipientsOnEtherscan).toBe(
+            true,
+        );
+    });
+
+    test("Settings shows both settings unticked, and ticking one there stores it", async () => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        expect(page.node("settings-use-blockscout").checked).toBe(false);
+        expect(
+            page.node("settings-check-recipients-on-etherscan").checked,
+        ).toBe(false);
+
+        await setBox(page, "settings-use-blockscout", true);
+        expect(page.storage.read("autistmask").useBlockscout).toBe(true);
+        await setBox(page, "settings-check-recipients-on-etherscan", true);
+        expect(page.storage.read("autistmask").checkRecipientsOnEtherscan).toBe(
+            true,
+        );
+    });
+
+    // A token the user tracks, and an untracked one that Blockscout reported.
+    // Both are written in lower case, because the balance rows' and the
+    // dropdown's token ids are compared in lower case below.
+    const TRACKED = "0xbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb";
+    const UNTRACKED = TOKEN_ADDRESS.toLowerCase();
+    const SECOND_ADDRESS = "0x3333333333333333333333333333333333333333";
+
+    function tokenRow(address, symbol) {
+        return {
+            address,
+            name: symbol,
+            symbol,
+            decimals: 18,
+            balance: "5.0",
+            holders: 50000,
+        };
+    }
+
+    // AddressDetail of the first of two addresses, as a reopened popup draws
+    // it. Both addresses hold the tracked token. While "Use Blockscout" is on,
+    // both hold the untracked one too.
+    function onAddressDetail(useBlockscout) {
+        const profile = unversionedValidProfile({
+            useBlockscout,
+            currentView: "address",
+            viewStack: ["main"],
+            selectedWallet: 0,
+            selectedAddress: 0,
+            trackedTokens: [
+                { address: TRACKED, name: "TRK", symbol: "TRK", decimals: 18 },
+            ],
+        });
+        const wallet = profile.wallets[0];
+        wallet.nextIndex = 2;
+        wallet.addresses.push({ address: SECOND_ADDRESS, balance: "0.0" });
+        for (const addr of wallet.addresses) {
+            addr.tokenBalances = useBlockscout
+                ? [tokenRow(TRACKED, "TRK"), tokenRow(UNTRACKED, "TST")]
+                : [tokenRow(TRACKED, "TRK")];
+        }
+        return profile;
+    }
+
+    // The token ids of the options created after the first `from` elements.
+    // The page stub keeps no children, so this reads the options for Send's
+    // dropdown from the elements the page created.
+    function optionsSince(page, from) {
+        return page.document.created
+            .slice(from)
+            .filter((el) => el.tagName === "OPTION")
+            .map((el) => el.value.toLowerCase());
+    }
+
+    test("unticking Use Blockscout from AddressDetail's gear takes the untracked token off AddressDetail, Send's dropdown and Home on Back", async () => {
+        const page = await bootPopup(onAddressDetail(true));
+        expect(page.visibleViews()).toEqual(["address"]);
+        expect(page.node("address-balances").innerHTML).toContain(UNTRACKED);
+
+        await page.click("btn-settings");
+        await setBox(page, "settings-use-blockscout", false);
+        const from = page.document.created.length;
+        await page.click("btn-settings-back");
+
+        expect(page.visibleViews()).toEqual(["address"]);
+        const balances = page.node("address-balances").innerHTML;
+        expect(balances).toContain(TRACKED);
+        expect(balances).not.toContain(UNTRACKED);
+        expect(page.hidden("address-tokens-note")).toBe(false);
+        expect(optionsSince(page, from)).toEqual([TRACKED]);
+
+        await page.click("btn-send");
+        expect(page.visibleViews()).toEqual(["send"]);
+        expect(page.hidden("send-token-dropdown")).toBe(false);
+        expect(page.hidden("send-tokens-note")).toBe(false);
+
+        await page.click("btn-send-back");
+        await page.click("btn-address-back");
+        expect(page.visibleViews()).toEqual(["main"]);
+        const home = page.node("wallet-list").innerHTML;
+        expect(home).toContain(TRACKED);
+        expect(home).not.toContain(UNTRACKED);
+
+        const stored = page.storage.read("autistmask");
+        for (const addr of stored.wallets[0].addresses) {
+            expect(
+                addr.tokenBalances.map((row) => row.address.toLowerCase()),
+            ).toEqual([TRACKED]);
+        }
+    });
+
+    // Send's dropdown was filled under the old setting, and Back cannot draw
+    // Send again. So Back lands on the screen under it.
+    test.each([
+        ["unticking", true],
+        ["ticking", false],
+    ])(
+        "%s Use Blockscout from Send's gear lands Back on AddressDetail",
+        async (_how, before) => {
+            const page = await bootPopup(onAddressDetail(before));
+            await page.click("btn-send");
+            expect(page.visibleViews()).toEqual(["send"]);
+
+            await page.click("btn-settings");
+            await setBox(page, "settings-use-blockscout", !before);
+            await page.click("btn-settings-back");
+            expect(page.visibleViews()).toEqual(["address"]);
+            expect(page.hidden("address-tokens-note")).toBe(!before);
+        },
+    );
+
+    test("Send says under its token dropdown that only tracked tokens are listed while Use Blockscout is off", async () => {
+        const off = await bootPopup(onAddressDetail(false));
+        await off.click("btn-send");
+        expect(off.hidden("send-token-dropdown")).toBe(false);
+        expect(off.hidden("send-tokens-note")).toBe(false);
+        cleanupPopup();
+
+        const on = await bootPopup(onAddressDetail(true));
+        await on.click("btn-send");
+        expect(on.hidden("send-token-dropdown")).toBe(false);
+        expect(on.hidden("send-tokens-note")).toBe(true);
+    });
+
+    test("Send opened from AddressToken shows neither the dropdown nor its line", async () => {
+        const page = await bootPopup({
+            ...onAddressDetail(false),
+            currentView: "address-token",
+            viewStack: ["main", "address"],
+            selectedToken: "ETH",
+        });
+        expect(page.visibleViews()).toEqual(["address-token"]);
+        await page.click("btn-address-token-send");
+        expect(page.visibleViews()).toEqual(["send"]);
+        expect(page.hidden("send-token-dropdown")).toBe(true);
+        expect(page.hidden("send-token-static")).toBe(false);
+    });
+
+    test("DeleteAddress says only tracked tokens are listed while Use Blockscout is off", async () => {
+        for (const useBlockscout of [false, true]) {
+            const page = await bootPopup(onAddressDetail(useBlockscout));
+            require("../src/popup/views/deleteAddress").show(0, 1);
+            expect(page.visibleViews()).toEqual(["delete-address-confirm"]);
+            expect(page.hidden("delete-address-tokens-note")).toBe(
+                useBlockscout,
+            );
+            cleanupPopup();
+        }
+    });
+
+    // The token ids of the first address's balances in the stored profile.
+    function storedTokens(page) {
+        return page.storage
+            .read("autistmask")
+            .wallets[0].addresses[0].tokenBalances.map((row) =>
+                row.address.toLowerCase(),
+            );
+    }
+
+    // Turning the setting off dropped the untracked token. A refresh that
+    // started while the setting was on still saves its balances when it
+    // returns, but not that token. The same refresh in the background is in
+    // tests/backgroundStateIsolation.test.js.
+    test("a refresh that returns after Use Blockscout was turned off saves its balances without the untracked token", async () => {
+        const page = await bootPopup(onAddressDetail(true));
+        const { refreshBalances: held } = require("../src/shared/balances");
+        let answer;
+        held.mockImplementationOnce(async (wallets) => {
+            await new Promise((resolve) => {
+                answer = resolve;
+            });
+            wallets[0].addresses[0].balance = "7.0";
+            wallets[0].addresses[0].tokenBalances = [
+                tokenRow(TRACKED, "TRK"),
+                tokenRow(UNTRACKED, "TST"),
+            ];
+        });
+        const ticking = page.tick();
+        await page.settle();
+
+        await page.click("btn-settings");
+        await setBox(page, "settings-use-blockscout", false);
+        answer();
+        await ticking;
+
+        expect(
+            page.storage.read("autistmask").wallets[0].addresses[0].balance,
+        ).toBe("7.0");
+        expect(storedTokens(page)).toEqual([TRACKED]);
+        await page.click("btn-settings-back");
+        expect(page.node("address-balances").innerHTML).not.toContain(
+            UNTRACKED,
+        );
+    });
+
+    // Another page saves `change` over the stored profile. The browser is not
+    // made to tell this page, so this page sees the change only by reading the
+    // stored profile.
+    function anotherPageSaves(page, change) {
+        page.storage.write("autistmask", {
+            ...page.storage.read("autistmask"),
+            ...change,
+        });
+    }
+
+    test.each([
+        ["off", true, false],
+        ["on", false, true],
+    ])(
+        "after another page turns Use Blockscout %s, this page takes the change and its next refresh is saved",
+        async (_how, before, after) => {
+            const page = await bootPopup(onAddressDetail(before));
+            // The refresh answers as it does under the stored setting.
+            const { refreshBalances: held } = require("../src/shared/balances");
+            held.mockImplementationOnce(async (wallets) => {
+                const addr = wallets[0].addresses[0];
+                addr.balance = "7.0";
+                addr.tokenBalances = after
+                    ? [tokenRow(TRACKED, "TRK"), tokenRow(UNTRACKED, "TST")]
+                    : [tokenRow(TRACKED, "TRK")];
+            });
+
+            anotherPageSaves(page, { useBlockscout: after });
+            await page.tick();
+
+            expect(
+                page.storage.read("autistmask").wallets[0].addresses[0].balance,
+            ).toBe("7.0");
+            expect(storedTokens(page)).toEqual(
+                after ? [TRACKED, UNTRACKED] : [TRACKED],
+            );
+            expect(page.hidden("address-tokens-note")).toBe(after);
+        },
+    );
+
+    test.each([
+        ["off", true, false],
+        ["on", false, true],
+    ])(
+        "after another page turns Check recipients on Etherscan %s, this page's next Etherscan check follows the stored setting",
+        async (_how, before, after) => {
+            const page = await bootPopup(
+                onConfirmScreen({ checkRecipientsOnEtherscan: before }),
+            );
+            anotherPageSaves(page, { checkRecipientsOnEtherscan: after });
+            const from = fetched().length;
+            require("../src/popup/views/confirmTx").show({
+                token: "ETH",
+                from: ADDRESS,
+                to: RECIPIENT,
+                amount: "0.1",
+                chainId: "0x1",
+            });
+            await page.settle();
+
+            // The page also takes the change and draws ConfirmTx again, which
+            // checks once more. So the test counts each URL once, however often
+            // it was asked for.
+            const asked = new Set(
+                fetched().slice(from).filter(blockscoutOrEtherscan),
+            );
+            expect([...asked]).toEqual(
+                after ? ["https://etherscan.io/address/" + RECIPIENT] : [],
+            );
+        },
+    );
+
+    // Another page's save of the whole profile with `change`, which the
+    // browser announces to this page as it announces any write.
+    async function anotherPageAnnounces(page, change) {
+        await page.storage.local.set({
+            autistmask: { ...page.storage.read("autistmask"), ...change },
+        });
+        await page.settle();
+    }
+
+    test("a page open on AddressDetail draws it again when another page turns Use Blockscout off", async () => {
+        const page = await bootPopup(onAddressDetail(true));
+        expect(page.hidden("address-tokens-note")).toBe(true);
+
+        await anotherPageAnnounces(page, { useBlockscout: false });
+
+        expect(page.visibleViews()).toEqual(["address"]);
+        expect(page.hidden("address-tokens-note")).toBe(false);
+        expect(page.node("address-balances").innerHTML).not.toContain(
+            UNTRACKED,
+        );
+        expect(storedTokens(page)).toEqual([TRACKED]);
+    });
+
+    test("a page open on ConfirmTx draws it again when another page turns Check recipients on Etherscan off", async () => {
+        const page = await bootPopup(
+            onConfirmScreen({ checkRecipientsOnEtherscan: true }),
+        );
+        expect(page.hidden("confirm-etherscan-note")).toBe(true);
+
+        await anotherPageAnnounces(page, { checkRecipientsOnEtherscan: false });
+
+        expect(page.visibleViews()).toEqual(["confirm-tx"]);
+        expect(page.hidden("confirm-etherscan-note")).toBe(false);
+    });
+});

tests/chainSwitchGate.test.js

@@ -446,7 +446,10 @@ describe("switching the network in Settings tells every open tab", () => {
         global.chrome.runtime.sendMessage = (msg) => {
             bg.send(msg, POPUP);
         };
-        await require("../src/shared/state").loadState();
+        const { state, loadState } = require("../src/shared/state");
+        await loadState();
+        // Set by showView(), which is mocked above.
+        state.currentView = "settings";
         require("../src/popup/views/settings").init({
             pageClosed: new AbortController().signal,
         });

tests/coldWorkerChainId.test.js

@@ -73,6 +73,8 @@ function loadColdWorker(networkId, opts) {
     jest.doMock("../src/shared/balances", () => ({
         getProvider: () => ({}),
         refreshBalances: options.refreshBalances || jest.fn(async () => {}),
+        dropUntrackedTokens: jest.requireActual("../src/shared/balances")
+            .dropUntrackedTokens,
     }));
     jest.doMock("../src/shared/phishingDomains", () => ({
         isPhishingDomain: () => false,

tests/confirmTxAmount.test.js

@@ -108,7 +108,10 @@ global.fetch = jest.fn(() => {
 });
 
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+    runtime: { sendMessage() {} },
+};
 
 // A stub DOM: every id resolves to a recording element.
 const elements = new Map();
@@ -243,6 +246,10 @@ async function openSend(token, tokenUnits = null) {
     ];
     state.selectedWallet = 0;
     state.selectedAddress = 0;
+    // Blockscout is asked only while the stored "Use Blockscout" is on. The
+    // screens save this page's copy of "Use Blockscout" over the stored one. So
+    // the page's copy is turned on here too.
+    state.useBlockscout = true;
     await refreshBalances(
         state.wallets,
         "https://rpc.example.invalid",

tests/confirmTxLateResult.test.js

@@ -50,8 +50,14 @@ function explorerPage(title) {
 // The explorer labels no address.
 global.fetch = jest.fn(async () => explorerPage("Etherscan"));
 
+// The Etherscan label check is made, so its box can be shown.
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };
+global.chrome = {
+    storage: makeStorageStub({
+        autistmask: { checkRecipientsOnEtherscan: true },
+    }),
+    runtime: { sendMessage() {} },
+};
 
 // A stub DOM: every id resolves to a recording element.
 const elements = new Map();

tests/confirmTxNetworkSwitch.test.js

@@ -142,13 +142,19 @@ jest.mock("../src/popup/views/txStatus", () => ({
 }));
 
 // The Etherscan label check is its only caller here: the explorer pages it
-// asks for are recorded, and nothing is fetched.
+// asks for are recorded, and nothing is fetched. The stored profile has the
+// check turned on.
 global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
 
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };
+global.chrome = {
+    storage: makeStorageStub({
+        autistmask: { checkRecipientsOnEtherscan: true },
+    }),
+    runtime: { sendMessage() {} },
+};
 
 // A stub DOM: every id resolves to a recording element.
 const elements = new Map();

tests/contractCreation.test.js

@@ -297,6 +297,8 @@ describe.each([
         state.selectedWallet = 0;
         state.selectedAddress = 0;
         state.selectedToken = "ETH";
+        // The history is Blockscout's.
+        state.useBlockscout = true;
     });
 
     test("a contract creation's row says so, with no colour dot and no address line", async () => {

tests/e2e/firefox/run.js

@@ -867,6 +867,14 @@ step(
             "the page was not told of the approved switch: " +
                 JSON.stringify(events),
         );
+        // The popup, open all along, shows the new network
+        // (https://git.eeqj.de/sneak/AutistMask/issues/650).
+        await d.switchToWindow(env.popupWindow);
+        await d.waitFor(
+            "the open popup to show the testnet banner",
+            `const banner = document.getElementById("debug-banner");
+             return banner !== null && banner.textContent === "[TESTNET]";`,
+        );
 
         await openNetworkPrompt(env, "switch-restore", sepolia, mainnet);
         await d.click("#btn-approve-network");
@@ -881,6 +889,10 @@ step(
             isDeepStrictEqual(await storedNetwork(env), before),
             "switching back did not restore the mainnet network and endpoints",
         );
+        await d.waitFor(
+            "the open popup to drop the testnet banner",
+            `return document.getElementById("debug-banner") === null;`,
+        );
         await d.switchToWindow(env.dappWindow);
     },
 );
@@ -1023,11 +1035,14 @@ step(
     },
 );
 
+// A closed approval window leaves its request pending, and the toolbar button
+// opens it (https://git.eeqj.de/sneak/AutistMask/issues/673). WebDriver cannot
+// see the toolbar popup, so its page is opened in a tab, at the URL the
+// extension put on the button.
 step(
-    "closing an approval window rejects the request with 4001",
+    "a closed approval window leaves the request pending until it is rejected",
     async (env) => {
         const d = env.driver;
-        const before = env.server.broadcast.length;
 
         await d.switchToWindow(env.dappWindow);
         await startRequest(d, "sign-closed", "personal_sign", [
@@ -1041,15 +1056,45 @@ step(
 
         // Closed, not rejected: this is the windows.onRemoved path, which can
         // only fire if windows.create() handed back a window id for the
-        // approval to be matched against — call site 4 in the issue, and the
+        // approval to be matched against. Without that id the toolbar button
-        // reason suppressing that write-back turns this step red.
+        // never opens the approval, and this step fails.
         await d.closeWindow(env.dappWindow);
-
+        const outcome = await settleRequest(d, "sign-closed", 2000);
-        await assertUserRejection(d, "sign-closed", "a closed approval window");
         assert(
-            env.server.broadcast.length === before,
+            outcome.settled === "pending",
-            "a closed approval window still put a transaction on the node",
+            "closing the approval window answered the page: " +
+                JSON.stringify(outcome),
         );
+
+        await d.switchToWindow(env.popupWindow);
+        const url = await d.executeAsync(
+            `const done = arguments[arguments.length - 1];
+             browser.browserAction.getPopup({}).then(done, (e) => done(String(e)));`,
+        );
+        assert(
+            url.includes("?approval="),
+            "the toolbar button does not open the pending approval: " + url,
+        );
+        const reopened = await d.newWindow("tab");
+        await d.switchToWindow(reopened);
+        await d.navigate(url);
+        await d.waitVisible("#view-approve-sign");
+        await d.click("#btn-reject-sign");
+
+        await d.switchToWindow(env.dappWindow);
+        await assertUserRejection(
+            d,
+            "sign-closed",
+            "the signature request rejected from the toolbar button",
+        );
+
+        // A page may close only a window a script opened, so the tab can
+        // still be open.
+        const left = await d.findWindow((u) => u.includes("?approval="));
+        if (left) {
+            await d.switchToWindow(left);
+            await d.closeWindow(env.dappWindow);
+        }
     },
 );
 

tests/e2e/network.js

@@ -653,6 +653,12 @@ function traceEnabled(raw) {
  *   confirmed receipt instead of null, so a wait screen resolves.
  * @param {boolean} [opts.failReceiptLookup]  answer eth_getTransactionReceipt
  *   with an error, so every receipt lookup fails; read at request time.
+ * @param {string} [opts.etherscanLabel]  the label Etherscan's page gives the
+ *   address asked about, such as "Fake_Phishing1"; none when unset. Read at
+ *   request time.
+ * @param {object[]} [opts.requests]  a list for the requests this handler
+ *   sees. Each is appended in order as { method, url, fromWorker }, whether it
+ *   came from a popup page or the background worker.
  * @returns {Promise<{waitForServiceWorkerTraffic: (ms: number) =>
  *   Promise<string|null>}>}
  */
@@ -691,6 +697,13 @@ async function installNetworkStubs(ctx, opts) {
             const origin = fromWorker ? "[sw] " : "[page] ";
             console.log("# routed " + origin + req.method() + " " + req.url());
         }
+        if (Array.isArray(opts.requests)) {
+            opts.requests.push({
+                method: req.method(),
+                url: req.url(),
+                fromWorker,
+            });
+        }
 
         // JSON-RPC endpoint (any host): a POST with a JSON-RPC body.
         if (req.method() === "POST") {
@@ -762,12 +775,20 @@ async function installNetworkStubs(ctx, opts) {
             return route.fulfill({ status: 204, body: "" });
         }
 
-        // Best-effort Etherscan address labels: served as an empty page.
+        // Best-effort Etherscan address labels: served as an empty page, or
+        // as a page labelling the address with opts.etherscanLabel.
         if (url.hostname.endsWith("etherscan.io")) {
+            const title = opts.etherscanLabel
+                ? "<title>" +
+                  opts.etherscanLabel +
+                  " | Address: " +
+                  p.split("/").pop() +
+                  " | Etherscan</title>"
+                : "";
             return route.fulfill({
                 status: 200,
                 contentType: "text/html",
-                body: "<html><body></body></html>",
+                body: "<html><head>" + title + "</head><body></body></html>",
             });
         }
 

tests/e2e/run.js

@@ -269,6 +269,69 @@ test("the exact confirmation phrase erases the record and reloads into Welcome (
     }
 });
 
+// ------------------ Blockscout and Etherscan are sent no user data (#668)
+//
+// A fresh install sends Blockscout and Etherscan none of the user's data until
+// the user turns on "Use Blockscout" or "Check recipients on Etherscan". One
+// request still reaches Blockscout while "Use Blockscout" is off: pressing
+// "Save" beside the Blockscout URL asks that URL for `/stats`. That request
+// carries no user data.
+//
+// The route handler in tests/e2e/network.js records in env.routeOpts.requests
+// every request the extension makes, from its pages and its background worker.
+// Recording starts when launch() in tests/e2e/harness.js installs that handler,
+// before the first popup page opens. The background worker starts earlier, but
+// it makes no request while it starts up.
+//
+// Before either setting is changed, these tests drive:
+//
+//   - Home, AddressDetail, AddressToken and ConfirmTx
+//   - the background's own balance refresh
+//
+// Then they turn each setting on and watch its requests start. "Use Blockscout"
+// is also turned off once and on again, to see an untracked token leave every
+// list. TransactionDetail, which also asks Blockscout, is left to the unit
+// tests in tests/blockscoutEtherscanSettings.test.js.
+
+// The line shown in place of the three transaction histories while "Use
+// Blockscout" is off. Written out here rather than imported, so the assertion
+// does not compare the popup with itself.
+const HISTORY_OFF =
+    'No transaction history is shown, because "Use Blockscout" is off in Settings.';
+
+// The requests made so far to Blockscout or Etherscan.
+function explorerRequests(env) {
+    return env.routeOpts.requests.filter(({ url }) => {
+        const host = new URL(url).hostname;
+        return host.endsWith("blockscout.com") || host.endsWith("etherscan.io");
+    });
+}
+
+// Waits until the list `listId` shows the line saying "Use Blockscout" is off.
+async function waitForHistoryOff(page, listId) {
+    await page.waitForFunction(
+        ([id, want]) => document.getElementById(id).textContent.trim() === want,
+        [listId, HISTORY_OFF],
+        { timeout: 15000 },
+    );
+}
+
+test("Welcome offers Use Blockscout and Check recipients on Etherscan, both unticked (#668)", async (env) => {
+    await visible(env.page, "#view-welcome");
+    for (const id of [
+        "welcome-use-blockscout",
+        "welcome-check-recipients-on-etherscan",
+    ]) {
+        const st = await controlState(env.page, id);
+        assert(st !== null, "Welcome has no #" + id);
+        assert(
+            st.tag === "input" && st.type === "checkbox",
+            "#" + id + " is a <" + st.tag + " type=" + st.type + ">",
+        );
+        assert(st.checked === false, "#" + id + " is ticked on a new install");
+    }
+});
+
 // The address scan that follows creating the wallet is held, so the popup
 // reloads while it is in flight. As for the reloads mid-refresh further down,
 // the assertion for that is the harness's own: a console.error from the page
@@ -296,6 +359,261 @@ test("wallet creation through the UI reaches the main view, and reloading mid-sc
     assert(addrCount > 0, "no addresses rendered in the wallet list");
 });
 
+test("with neither setting changed, Home, AddressDetail, AddressToken and ConfirmTx say what is off (#668)", async (env) => {
+    // Funded, so Send leads to the confirmation screen.
+    env.routeOpts.ethBalanceWei = toHexWei(FUNDED_ETH_WEI);
+    try {
+        await visible(env.page, "#view-main");
+        await waitForHistoryOff(env.page, "home-tx-list");
+        await visible(env.page, "#home-tokens-note");
+        await env.page.waitForFunction(
+            (want) =>
+                document
+                    .getElementById("wallet-list")
+                    .textContent.includes(want),
+            quantity(FUNDED_ETH_WEI),
+            { timeout: 60000 },
+        );
+
+        await openAddressDetail(env.page);
+        await waitForHistoryOff(env.page, "tx-list");
+        await visible(env.page, "#address-tokens-note");
+
+        await env.page.locator('#address-balances [data-token="ETH"]').click();
+        await visible(env.page, "#view-address-token");
+        await waitForHistoryOff(env.page, "address-token-tx-list");
+        await env.page.click("#btn-address-token-back");
+        await visible(env.page, "#view-address");
+
+        await goToConfirm(env.page, {
+            token: "ETH",
+            balance: FUNDED_ETH_TEXT + " ETH",
+            amount: COMFORTABLE_AMOUNT,
+        });
+        await waitForEstimate(env.page);
+        await visible(env.page, "#confirm-etherscan-note");
+        assert(
+            !(await env.page.isVisible("#confirm-etherscan-warning")),
+            "ConfirmTx keeps the Etherscan warning's place while no Etherscan check is made",
+        );
+        await backToAddress(env.page);
+    } finally {
+        env.routeOpts.ethBalanceWei = null;
+    }
+});
+
+// The background refreshes balances on its alarm, once a minute. It skips a
+// refresh when the stored record says one ran in the last 30 seconds. The open
+// popup's own refresh runs every 10. So the popup is closed first. The test then
+// has the background worker set the stored time of the last refresh to 0, so
+// its next alarm runs a refresh.
+test("with neither setting changed, nothing has reached Blockscout or Etherscan, the background's refresh included (#668)", async (env) => {
+    await waitForPersisted(
+        env.page,
+        "currentView",
+        "address",
+        "before the popup is closed",
+    );
+    await env.page.close();
+    const [worker] = env.ctx.serviceWorkers();
+    await worker.evaluate(
+        () =>
+            new Promise((resolve) => {
+                chrome.storage.local.get("autistmask", (r) => {
+                    const record = r.autistmask;
+                    record.lastBalanceRefresh = 0;
+                    chrome.storage.local.set({ autistmask: record }, resolve);
+                });
+            }),
+    );
+    const before = env.routeOpts.requests.length;
+    const deadline = Date.now() + 75000;
+    while (
+        !env.routeOpts.requests
+            .slice(before)
+            .some((r) => r.fromWorker && r.method === "POST")
+    ) {
+        assert(
+            Date.now() < deadline,
+            "the background's balance refresh never asked the RPC endpoint",
+        );
+        await sleep(250);
+    }
+    // The refresh's RPC reads and any Blockscout request start together.
+    await sleep(3000);
+
+    const seen = explorerRequests(env);
+    assert(
+        seen.length === 0,
+        "a fresh install asked Blockscout or Etherscan: " +
+            JSON.stringify(seen),
+    );
+    // The watch saw the popup's own traffic as well as the worker's.
+    assert(
+        env.routeOpts.requests.some((r) => !r.fromWorker),
+        "no request from the popup was recorded",
+    );
+    // The popup reopens on the address screen the test above left it on.
+    env.page = await openPopup(env.ctx, env.popupUrl);
+    await visible(env.page, "#view-address");
+});
+
+// Ticked from AddressDetail's gear, so Back lands on the screen that said the
+// setting is off.
+test("turning on Use Blockscout from AddressDetail's gear asks Blockscout for that screen's history on Back, then for the tokens (#668)", async (env) => {
+    await openAddressDetail(env.page);
+    await waitForHistoryOff(env.page, "tx-list");
+    await openSettings(env.page);
+    await env.page.check("#settings-use-blockscout");
+    await waitForPersisted(env.page, "useBlockscout", true, "once ticked");
+    const historyAsked = env.page.waitForRequest(
+        (r) =>
+            r.url().includes("blockscout.com") &&
+            r.url().endsWith("/transactions"),
+    );
+    const tokensAsked = env.page.waitForRequest(
+        (r) => r.url().endsWith("/token-balances"),
+        { timeout: 30000 },
+    );
+    await env.page.click("#btn-settings-back");
+    await visible(env.page, "#view-address");
+    await historyAsked;
+    await env.page.waitForFunction(
+        () =>
+            document
+                .getElementById("tx-list")
+                .textContent.includes("No transactions found."),
+        null,
+        { timeout: 15000 },
+    );
+    assert(
+        !(await env.page.isVisible("#address-tokens-note")),
+        "AddressDetail still says only tracked tokens are listed",
+    );
+
+    await goHome(env.page);
+    await tokensAsked;
+    await env.page.waitForFunction(
+        () =>
+            document
+                .getElementById("home-tx-list")
+                .textContent.includes("No transactions found."),
+        null,
+        { timeout: 15000 },
+    );
+    assert(
+        !(await env.page.isVisible("#home-tokens-note")),
+        "Home still says only tracked tokens are listed",
+    );
+});
+
+// Unticked from AddressDetail's gear while the address holds the stub token,
+// which the user has not tracked and only Blockscout reports. Ticked again at
+// the end, so the rest of the run has Blockscout as before.
+test("turning off Use Blockscout from AddressDetail's gear takes an untracked token off AddressDetail, Send and Home on Back (#668)", async (env) => {
+    env.routeOpts.ethBalanceWei = toHexWei(FUNDED_ETH_WEI);
+    env.routeOpts.seedTokenBalance = true;
+    const tokenRow = '[data-token="' + STUB_TOKEN.address + '"]';
+    try {
+        await settleOnMain(env, { ethWei: FUNDED_ETH_WEI, expectToken: true });
+        await openAddressDetail(env.page);
+        await visible(env.page, "#address-balances " + tokenRow);
+
+        await openSettings(env.page);
+        await env.page.uncheck("#settings-use-blockscout");
+        await waitForPersisted(
+            env.page,
+            "useBlockscout",
+            false,
+            "once unticked",
+        );
+        await env.page.click("#btn-settings-back");
+        await visible(env.page, "#view-address");
+        await visible(env.page, "#address-tokens-note");
+        assert(
+            (await env.page
+                .locator("#address-balances " + tokenRow)
+                .count()) === 0,
+            "AddressDetail still lists the untracked token",
+        );
+
+        await env.page.click("#btn-send");
+        await visible(env.page, "#view-send");
+        await visible(env.page, "#send-tokens-note");
+        const offered = await env.page.$$eval("#send-token option", (opts) =>
+            opts.map((opt) => opt.value.toLowerCase()),
+        );
+        assert(
+            !offered.includes(STUB_TOKEN.address),
+            "Send's dropdown still offers the untracked token",
+        );
+        await env.page.click("#btn-send-back");
+        await visible(env.page, "#view-address");
+
+        await goHome(env.page);
+        await visible(env.page, "#home-tokens-note");
+        assert(
+            (await env.page.locator("#wallet-list " + tokenRow).count()) === 0,
+            "Home still lists the untracked token",
+        );
+    } finally {
+        await openSettings(env.page);
+        await env.page.check("#settings-use-blockscout");
+        await waitForPersisted(env.page, "useBlockscout", true, "ticked again");
+        await env.page.click("#btn-settings-back");
+        env.routeOpts.ethBalanceWei = null;
+        env.routeOpts.seedTokenBalance = false;
+    }
+});
+
+// Ticked from ConfirmTx's gear, so Back lands on the screen that said no
+// Etherscan check was made. Left on for the rest of the run, so the later
+// confirmation screens are driven with the check made.
+test("turning on Check recipients on Etherscan from ConfirmTx's gear has ConfirmTx ask Etherscan on Back and show its label (#668)", async (env) => {
+    env.routeOpts.ethBalanceWei = toHexWei(FUNDED_ETH_WEI);
+    env.routeOpts.etherscanLabel = "Fake_Phishing668";
+    try {
+        await settleOnMain(env, { ethWei: FUNDED_ETH_WEI });
+        await goToConfirm(env.page, {
+            token: "ETH",
+            balance: FUNDED_ETH_TEXT + " ETH",
+            amount: COMFORTABLE_AMOUNT,
+        });
+        await visible(env.page, "#confirm-etherscan-note");
+
+        await openSettings(env.page);
+        await env.page.check("#settings-check-recipients-on-etherscan");
+        await waitForPersisted(
+            env.page,
+            "checkRecipientsOnEtherscan",
+            true,
+            "once ticked",
+        );
+        const before = env.routeOpts.requests.length;
+        await env.page.click("#btn-settings-back");
+        await visible(env.page, "#view-confirm-tx");
+        await visible(env.page, "#confirm-etherscan-warning", 30000);
+        assert(
+            !(await env.page.isVisible("#confirm-etherscan-note")),
+            "ConfirmTx says no Etherscan check was made, with the check on",
+        );
+        const asked = env.routeOpts.requests
+            .slice(before)
+            .map((r) => r.url.toLowerCase())
+            .filter((url) => url.includes("etherscan.io"));
+        assert(
+            asked.length === 1 &&
+                asked[0] ===
+                    "https://etherscan.io/address/" + STUB_COUNTERPARTY,
+            "ConfirmTx asked Etherscan for " + JSON.stringify(asked),
+        );
+        await backToAddress(env.page);
+    } finally {
+        env.routeOpts.ethBalanceWei = null;
+        env.routeOpts.etherscanLabel = null;
+    }
+});
+
 test("add token screen opens from address detail (#150)", async (env) => {
     await openAddressDetail(env.page);
     await env.page.click("#btn-add-token");
@@ -3480,6 +3798,24 @@ function hostileSymbolState(page, tokenAddress) {
 }
 
 test("a token whose symbol() returns markup renders as text (#307)", async (env) => {
+    // The stub token is no longer tracked from here on, so the explorer is
+    // what lists it, as it lists a token airdropped to the victim. A tracked
+    // token is listed from the RPC endpoint under the symbol it was added
+    // with, which the hostile symbol below never reaches
+    // (https://git.eeqj.de/sneak/AutistMask/issues/669).
+    await env.page.click("#btn-settings");
+    await visible(env.page, "#view-settings");
+    await env.page.click("#settings-tracked-tokens .btn-remove-token");
+    // The list is drawn again once the removal is saved.
+    await env.page.waitForFunction(
+        () =>
+            document
+                .getElementById("settings-tracked-tokens")
+                .innerText.trim() === "None",
+    );
+    await env.page.click("#btn-settings-back");
+    await visible(env.page, "#view-address");
+
     env.routeOpts.ethBalanceWei = toHexWei(FUNDED_ETH_WEI);
     env.routeOpts.seedTokenBalance = true;
     env.routeOpts.tokenSymbolOverride = HOSTILE_SYMBOL;
@@ -3774,11 +4110,12 @@ async function waitForApprovalWindow(ctx, timeout = 30000) {
 // reservation exists.
 // How long the tab creation above is given to take effect before the request
 // that raises the next prompt is issued. Dismissing a browser-action popup
-// disconnects its port, and src/background/index.js calls resetPopupUrl() on
+// disconnects its port, and src/background/index.js calls
-// that disconnect; issued too early, the next request's setPopup() is undone
+// updateToolbarPopup() on that disconnect; issued too early, the next
-// by the previous popup's teardown, chrome.action.openPopup() then rejects,
+// request's setPopup() is undone by the previous popup's teardown,
-// and the fallback window it opens dismisses the popup that was just raised —
+// chrome.action.openPopup() then rejects, and the fallback window it opens
-// which settles the fresh approval as a rejection before it can be seen.
+// dismisses the popup that was just raised — which settles the fresh approval
+// as a rejection before it can be seen.
 // Every one of those steps was observed. 1.5s is comfortably past it.
 const APPROVAL_TAB_SETTLE_MS = 1500;
 
@@ -3804,6 +4141,17 @@ async function reserveApprovalTab(env) {
     return env.approvalTab;
 }
 
+// The URL the extension has put on the action: the page the toolbar button
+// opens.
+function toolbarPopupUrl(env) {
+    return env.page.evaluate(
+        () =>
+            new Promise((resolve) => {
+                chrome.action.getPopup({}, (u) => resolve(String(u)));
+            }),
+    );
+}
+
 // The site-connection prompt: the window the extension opened if it managed
 // to open one, and the reserved tab at the action's approval URL otherwise.
 async function openSiteApprovalPopup(env, timeout = 30000) {
@@ -3814,12 +4162,7 @@ async function openSiteApprovalPopup(env, timeout = 30000) {
             .find((p) => !p.isClosed() && p.url().includes("?approval="));
         if (existing) return existing;
 
-        const url = await env.page.evaluate(
+        const url = await toolbarPopupUrl(env);
-            () =>
-                new Promise((resolve) => {
-                    chrome.action.getPopup({}, (u) => resolve(String(u)));
-                }),
-        );
         if (url.includes("?approval=")) {
             await env.approvalTab.goto(url);
             return env.approvalTab;
@@ -4691,6 +5034,116 @@ test("eth_sendTransaction rejected broadcasts nothing (#183)", async (env) => {
     );
 });
 
+// A transaction or signature approval stays pending when its window closes.
+// The browser can close that window when the user clicks away from it, for
+// example to copy the password from a password manager. The toolbar button then
+// opens the approval, and the user answers it there
+// (https://git.eeqj.de/sneak/AutistMask/issues/673).
+//
+// This closes the approval window of request `key` and checks that the page
+// has no answer. It then opens the approval again from the toolbar button.
+// Playwright cannot click that button, so its page is opened in a tab, at the
+// URL the extension put on the button.
+async function closeAndReopen(env, key, view) {
+    const approvalWindow = await waitForApprovalWindow(env.ctx);
+    await visible(approvalWindow, view);
+    await approvalWindow.close();
+
+    const outcome = await settleRequest(env.dapp, key, 2000);
+    assert(
+        outcome.settled === "pending",
+        "closing the approval window answered the page: " +
+            JSON.stringify(outcome),
+    );
+
+    const url = await toolbarPopupUrl(env);
+    assert(
+        url.includes("?approval="),
+        "the toolbar button does not open the pending approval: " + url,
+    );
+    const reopened = await env.ctx.newPage();
+    await reopened.goto(url);
+    await visible(reopened, view);
+    return reopened;
+}
+
+// The stub node answers every nonce request with 0, and the wallet refuses a
+// nonce it has already broadcast. A run can therefore approve one dApp
+// transaction only, so here the signature is approved and the transaction
+// rejected.
+test("a closed signature approval is signed from the toolbar button (#673)", async (env) => {
+    await startRequest(env.dapp, "sign-closed", "personal_sign", [
+        SIGN_HEX,
+        env.expectedAddress,
+    ]);
+    const popup = await closeAndReopen(
+        env,
+        "sign-closed",
+        "#view-approve-sign",
+    );
+    let outcome;
+    try {
+        await popup.fill("#approve-sign-password", PASSWORD);
+        await clickAndClose(popup, "#btn-approve-sign");
+        outcome = await settleRequest(env.dapp, "sign-closed");
+    } finally {
+        await closeApprovalPages(env.ctx);
+    }
+    assert(
+        outcome.settled === "resolved",
+        "personal_sign did not resolve: " + JSON.stringify(outcome),
+    );
+    const recovered = getAddress(
+        verifyMessage(getBytes(SIGN_HEX), outcome.result),
+    );
+    assert(
+        recovered === env.expectedAddress,
+        "the personal_sign signature recovers to " +
+            recovered +
+            ", not to the approved address " +
+            env.expectedAddress,
+    );
+
+    const url = await toolbarPopupUrl(env);
+    assert(
+        !url.includes("?approval="),
+        "the toolbar button still opens the answered approval: " + url,
+    );
+});
+
+test("a closed transaction approval is rejected from the toolbar button (#673)", async (env) => {
+    const before = env.routeOpts.broadcastTransactions.length;
+    await startRequest(env.dapp, "tx-closed", "eth_sendTransaction", [
+        {
+            from: env.expectedAddress,
+            to: STUB_COUNTERPARTY,
+            value: toQuantity(TX_VALUE_WEI),
+            data: TX_DATA,
+        },
+    ]);
+    const popup = await closeAndReopen(env, "tx-closed", "#view-approve-tx");
+    try {
+        await clickAndClose(popup, "#btn-reject-tx");
+        await assertUserRejection(
+            env.dapp,
+            "tx-closed",
+            "the transaction rejected from the toolbar button",
+        );
+    } finally {
+        await closeApprovalPages(env.ctx);
+    }
+    assert(
+        env.routeOpts.broadcastTransactions.length === before,
+        "a rejected transaction still reached the RPC",
+    );
+
+    const url = await toolbarPopupUrl(env);
+    assert(
+        !url.includes("?approval="),
+        "the toolbar button still opens the answered approval: " + url,
+    );
+});
+
 // The extension used to centre every approval window on the last focused
 // window. Centred on another approval window, the new one landed where the
 // browser refused to create it, and the request failed with no window at all
@@ -4734,8 +5187,8 @@ test("a prompt raised while another approval window has focus opens its own (#29
     });
     await visible(txWindow, "#view-approve-tx");
 
-    // Closing a window is refusing its prompt, so both answer 4001.
+    await clickAndClose(txWindow, "#btn-reject-tx");
-    await closeApprovalPages(env.ctx);
+    await clickAndClose(signWindow, "#btn-reject-sign");
     await assertUserRejection(env.dapp, "focus-tx", "the transaction prompt");
     await assertUserRejection(env.dapp, "focus-sign", "the sign prompt");
 });
@@ -4865,6 +5318,12 @@ test("a site's network switch changes nothing until the user approves it (#408)"
         "the page was not told of the approved switch: " +
             JSON.stringify(events),
     );
+    // The popup, open all along, shows the new network
+    // (https://git.eeqj.de/sneak/AutistMask/issues/650).
+    await env.page.waitForFunction(() => {
+        const banner = document.getElementById("debug-banner");
+        return banner !== null && banner.textContent === "[TESTNET]";
+    });
 
     const restored = await openNetworkPrompt(
         env,
@@ -4886,6 +5345,9 @@ test("a site's network switch changes nothing until the user approves it (#408)"
         isDeepStrictEqual(await storedNetwork(env.page), before),
         "switching back did not restore the mainnet network and endpoints",
     );
+    await env.page.waitForFunction(
+        () => document.getElementById("debug-banner") === null,
+    );
 });
 
 // Switching the network in Settings tells the page too, as an approved site
@@ -5231,10 +5693,17 @@ async function main() {
         seedReceipt: false,
         // Whether eth_getTransactionReceipt fails instead of answering (#315).
         failReceiptLookup: false,
+        // The label Etherscan's page gives an address, when it gives one
+        // (#668).
+        etherscanLabel: null,
         // Every raw signed transaction handed to eth_sendRawTransaction, in
         // order. The dApp transaction round trip asserts against these bytes
         // rather than against anything the extension reported about them.
         broadcastTransactions: [],
+        // Every request the extension makes, in order, from when launch()
+        // installs the route handler, before the first popup page opens
+        // (#668).
+        requests: [],
     };
 
     let session;
@@ -5326,9 +5795,11 @@ async function main() {
         // for the new one. After a test that passed, its windows get five
         // seconds to close, and one still open then fails the test: it should
         // have closed itself, and closing it here unreported would hide that.
-        // After a test that already failed, they are closed unreported, so
+        // After a test that already failed, they are closed unreported. That
-        // that a prompt it left unanswered does not refuse the next one from
+        // rejects a site-connection or network-switch prompt it left
-        // its site.
+        // unanswered, so the prompt does not refuse the next one from its
+        // site. A transaction or signature approval stays pending, and can
+        // fail the tests after it.
         if (!failure) {
             const deadline = Date.now() + 5000;
             let open;

tests/ensOffchainLookup.test.js

@@ -0,0 +1,114 @@
+// ENS lookups ask nothing but the RPC endpoint. A resolver can answer that a
+// name is resolved off-chain, naming a web address to fetch the answer from.
+// ethers fetches that address unless the provider has `disableCcipRead` set.
+// That request would carry the name to a server other than the RPC endpoint
+// (https://git.eeqj.de/sneak/AutistMask/issues/668). With the flag set, such a
+// name does not resolve.
+//
+// The test builds its provider with getProvider() and runs it against a fake
+// JSON-RPC node. The fake node answers through ethers' own request hook. The
+// hook also records the address of every request ethers makes, the off-chain
+// fetch included.
+
+const { FetchRequest, Interface } = require("ethers");
+const { getProvider } = require("../src/shared/balances");
+
+const RPC_URL = "https://rpc.example.invalid";
+const RESOLVER = "0x5555555555555555555555555555555555555555";
+const USER = "0x1111111111111111111111111111111111111111";
+const NAME = "offchain.eth";
+
+// The ENS registry's resolver(), and the resolver's functions ethers calls:
+//
+//   - the registry names RESOLVER for every name
+//   - the resolver says it resolves names through resolve()
+//   - it gives NAME as the reverse record of any address
+//   - it answers resolve() with the OffchainLookup error, which says the name
+//     is resolved off-chain
+const ens = new Interface([
+    "function resolver(bytes32) view returns (address)",
+    "function supportsInterface(bytes4) view returns (bool)",
+    "function name(bytes32) view returns (string)",
+    "function resolve(bytes, bytes) view returns (bytes)",
+    "error OffchainLookup(address sender, string[] urls, bytes callData, bytes4 callbackFunction, bytes extraData)",
+]);
+
+let asked;
+
+// One JSON-RPC answer. Anything but a call to one of the functions above is
+// refused.
+function reply(req) {
+    const envelope = { jsonrpc: "2.0", id: req.id };
+    const call =
+        req.method === "eth_call" ? ens.parseTransaction(req.params[0]) : null;
+    if (call === null) {
+        return {
+            ...envelope,
+            error: { code: -32601, message: "method not found" },
+        };
+    }
+    if (call.name === "resolve") {
+        const offchain = ens.encodeErrorResult("OffchainLookup", [
+            RESOLVER,
+            ["https://gateway.example.invalid/{sender}/{data}.json"],
+            "0x1234",
+            "0x12345678",
+            "0x",
+        ]);
+        return {
+            ...envelope,
+            error: { code: 3, message: "execution reverted", data: offchain },
+        };
+    }
+    const answers = {
+        resolver: [RESOLVER],
+        supportsInterface: [true],
+        name: [NAME],
+    };
+    return {
+        ...envelope,
+        result: ens.encodeFunctionResult(call.name, answers[call.name]),
+    };
+}
+
+beforeEach(() => {
+    asked = [];
+    FetchRequest.registerGetUrl(async (req) => {
+        asked.push(req.url);
+        // Any other address is the off-chain fetch, answered as not found.
+        if (req.url !== RPC_URL) {
+            return {
+                statusCode: 404,
+                statusMessage: "Not Found",
+                headers: {},
+                body: null,
+            };
+        }
+        const body = JSON.parse(Buffer.from(req.body).toString("utf8"));
+        const answer = Array.isArray(body) ? body.map(reply) : reply(body);
+        return {
+            statusCode: 200,
+            statusMessage: "OK",
+            headers: { "content-type": "application/json" },
+            body: Buffer.from(JSON.stringify(answer)),
+        };
+    });
+});
+
+afterEach(() => {
+    FetchRequest.registerGetUrl(FetchRequest.createGetUrlFunc());
+});
+
+test("a name typed into Send that is resolved off-chain does not resolve, and only the RPC endpoint is asked", async () => {
+    const provider = getProvider(RPC_URL, "mainnet");
+    const [outcome] = await Promise.allSettled([provider.resolveName(NAME)]);
+    expect(asked.filter((url) => url !== RPC_URL)).toEqual([]);
+    expect(outcome).toEqual({ status: "fulfilled", value: null });
+});
+
+test("the reverse lookup of a user's address whose name is resolved off-chain finds no name, and only the RPC endpoint is asked", async () => {
+    const provider = getProvider(RPC_URL, "mainnet");
+    const [outcome] = await Promise.allSettled([provider.lookupAddress(USER)]);
+    expect(asked.filter((url) => url !== RPC_URL)).toEqual([]);
+    expect(outcome).toEqual({ status: "fulfilled", value: null });
+});

tests/fabricatedDecimals.test.js

@@ -35,8 +35,11 @@ global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub() };
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+};
 
 const { AbiCoder, Interface } = require("ethers");
 const { ERC20_ABI } = require("../src/shared/constants");
@@ -165,6 +168,9 @@ beforeEach(() => {
     debugFetch.mockReset();
     state.trackedTokens = [];
     state.wallets = [];
+    // The approval screens read the explorer's report only while the page's
+    // "Use Blockscout" is on.
+    state.useBlockscout = true;
 });
 
 describe("what fetchTokenBalances stores for an absent scale", () => {

tests/holders.test.js

@@ -21,7 +21,11 @@ jest.mock("../src/shared/log", () => ({
 global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
-global.chrome = { storage: { local: {} } };
+// Blockscout is asked only while the stored "Use Blockscout" is on.
+const { makeStorageStub } = require("./support/storageStub");
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+};
 
 const {
     LOW_HOLDER_THRESHOLD,

tests/manifest.test.js

@@ -165,6 +165,15 @@ describe("declared icons", () => {
     });
 });
 
+// Firefox gives a page in a private window locks of its own, so that page's
+// save could land between the background's read and its write (README,
+// "Stored state and its version").
+describe("private windows", () => {
+    test("a page in a firefox private window cannot read or write extension storage", () => {
+        expect(readManifest("firefox").incognito).toBe("not_allowed");
+    });
+});
+
 describe("shipped Content Security Policy", () => {
     // MV3 takes an object and applies extension_pages to the popup and the
     // background service worker, which is where libsodium runs.

tests/nativeCurrency.test.js

@@ -436,6 +436,13 @@ describe.each([
         });
 
         test("the transaction detail screen's type line and fee", async () => {
+            // The fee is Blockscout's, asked for only while the stored "Use
+            // Blockscout" is on.
+            state.useBlockscout = true;
+            global.chrome.storage.write("autistmask", {
+                ...global.chrome.storage.read("autistmask"),
+                useBlockscout: true,
+            });
             debugFetch.mockImplementationOnce(async () => ({
                 ok: true,
                 status: 200,

tests/persistedEntryFloors.test.js

@@ -286,8 +286,12 @@ describe("a malformed fraudContracts", () => {
     function stubSendDocument() {
         const select = { innerHTML: "", children: [] };
         select.appendChild = (child) => select.children.push(child);
+        const elements = {
+            "send-token": select,
+            "send-tokens-note": { classList: { toggle: () => {} } },
+        };
         globalThis.document = {
-            getElementById: (id) => (id === "send-token" ? select : null),
+            getElementById: (id) => elements[id] || null,
             createElement: () => ({ value: "", textContent: "" }),
         };
         return select;

tests/persistedFieldContract.test.js

@@ -629,6 +629,21 @@ const CONTRACT = [
         // the falsy answer is also the DEFAULT_STATE default.
         falsy: [0],
     })),
+    // Anything but true is off for these three settings:
+    // - useBlockscout and checkRecipientsOnEtherscan let a request reach
+    //   another service.
+    // - allowWeakPasswords lets AddWallet accept a short password.
+    ...[
+        "useBlockscout",
+        "checkRecipientsOnEtherscan",
+        "allowWeakPasswords",
+    ].map((field) => ({
+        field,
+        kind: KIND.SCALAR,
+        hostile: [42, "notabool", { a: 1 }],
+        floorOnly: [0, null, "true"],
+        holds: (v) => v === false,
+    })),
 ];
 
 function siteMapHolds(v) {

tests/popupBoot.test.js

@@ -44,7 +44,9 @@ test("a flash message's timer does not fire after cleanupPopup()", async () => {
 
 // A boot onto a screen that sends a request no mocked module answers: that
 // request reaches the boot's fetch() stub, never the internet
-// (https://git.eeqj.de/sneak/AutistMask/issues/559).
+// (https://git.eeqj.de/sneak/AutistMask/issues/559). TransactionDetail asks
+// Blockscout only while "Use Blockscout" is on. ConfirmTx asks Etherscan only
+// while "Check recipients on Etherscan" is on. So the profile turns both on.
 function restoringOnto(view, viewData) {
     return unversionedValidProfile({
         currentView: view,
@@ -52,6 +54,8 @@ function restoringOnto(view, viewData) {
         selectedAddress: 0,
         viewStack: ["main"],
         viewData,
+        useBlockscout: true,
+        checkRecipientsOnEtherscan: true,
     });
 }
 

tests/popupFollowsNetworkSwitch.test.js

@@ -0,0 +1,300 @@
+// An open popup follows a network switch the background saves once the user
+// approves a site's request: it takes the new network from the stored record
+// and draws the screen it is on for it, as a switch in Settings does
+// (https://git.eeqj.de/sneak/AutistMask/issues/650). Driven through the real
+// popup over a stored profile on Ethereum Mainnet. The background's write is
+// the storage stub's set, which the stub reports to the page as the browser
+// does.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
+const { makeStorageStub } = require("./support/storageStub");
+const {
+    applyChainSwitchFields,
+    copyChainSwitchFields,
+} = require("../src/shared/chainSwitchFields");
+const { NETWORKS } = require("../src/shared/networks");
+const { STATE_SCHEMA_VERSION } = require("../src/shared/stateSchema");
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+const SEPOLIA_TOKEN = {
+    address: TOKEN_ADDRESS,
+    symbol: "TST",
+    decimals: 18,
+    name: "Test Token",
+};
+const MAINNET_TOKEN = {
+    address: "0x6B175474E89094C44Da98b954EedeAC495271d0F",
+    symbol: "DAI",
+    decimals: 18,
+    name: "Dai Stablecoin",
+};
+
+// A profile on Ethereum Mainnet that reopens the popup onto AddressDetail,
+// with DAI tracked there and TST tracked on Sepolia.
+function profileOnAddress() {
+    return unversionedValidProfile({
+        currentView: "address",
+        viewStack: ["main"],
+        selectedWallet: 0,
+        selectedAddress: 0,
+        trackedTokens: [MAINNET_TOKEN],
+        networkTrackedTokens: { sepolia: [SEPOLIA_TOKEN] },
+    });
+}
+
+// The popup reopened onto it.
+function bootOnAddress() {
+    return bootPopup(profileOnAddress());
+}
+
+// The background saves a switch to `networkId`, as its updateState() does
+// once the user approves a site's request.
+async function backgroundSwitch(page, networkId) {
+    const record = page.storage.read("autistmask");
+    applyChainSwitchFields(record, networkId);
+    await page.storage.local.set({ autistmask: record });
+    await page.settle();
+    await page.settle();
+}
+
+test("the popup open on AddressDetail shows the new network and its balances", async () => {
+    const page = await bootOnAddress();
+    expect(page.pageErrors).toEqual([]);
+    expect(page.visibleViews()).toEqual(["address"]);
+    expect(page.node("address-balances").innerHTML).toContain("DAI");
+    expect(page.node("debug-banner")).toBeNull();
+
+    await backgroundSwitch(page, "sepolia");
+
+    const { state } = require("../src/shared/state");
+    expect(state.networkId).toBe("sepolia");
+    expect(state.rpcUrl).toBe(NETWORKS.sepolia.defaultRpcUrl);
+    expect(page.visibleViews()).toEqual(["address"]);
+    const balances = page.node("address-balances").innerHTML;
+    expect(balances).toContain("TST");
+    expect(balances).toContain("SepoliaETH");
+    expect(balances).not.toContain("DAI");
+    expect(page.text("debug-banner")).toBe("[TESTNET]");
+
+    // Its next refresh runs on Sepolia, and what it fetched is stored.
+    await page.tick();
+    const { refreshBalances } = require("../src/shared/balances");
+    expect(refreshBalances.mock.lastCall[4]).toBe("sepolia");
+    const stored = page.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.lastBalanceRefresh).toBeGreaterThan(0);
+});
+
+test("the popup open on Settings shows the new network, and Back draws the screen beneath for it", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+    expect(page.visibleViews()).toEqual(["settings"]);
+
+    await backgroundSwitch(page, "sepolia");
+
+    expect(page.visibleViews()).toEqual(["settings"]);
+    expect(page.value("settings-network")).toBe("sepolia");
+    expect(page.value("settings-rpc")).toBe(NETWORKS.sepolia.defaultRpcUrl);
+    expect(page.node("settings-tracked-tokens").innerHTML).toContain("TST");
+    expect(page.text("debug-banner")).toBe("[TESTNET]");
+
+    await page.click("btn-settings-back");
+    expect(page.visibleViews()).toEqual(["address"]);
+    expect(page.node("address-balances").innerHTML).not.toContain("DAI");
+});
+
+// Neither can be drawn again for the new network: Send cannot be rendered from
+// saved state, and DAI was picked on Ethereum Mainnet, where alone it is
+// tracked. A reopened popup goes to Home in their place.
+test.each([
+    ["Send", (page) => page.click("btn-send")],
+    [
+        "AddressToken for DAI",
+        async (page) => {
+            const { state } = require("../src/shared/state");
+            state.selectedToken = MAINNET_TOKEN.address;
+            require("../src/popup/views/helpers").pushCurrentView();
+            require("../src/popup/views/addressToken").show();
+            await page.settle();
+        },
+    ],
+])("the popup open on %s goes to Home", async (_view, open) => {
+    const page = await bootOnAddress();
+    await open(page);
+    expect(page.visibleViews()).not.toEqual(["address"]);
+
+    await backgroundSwitch(page, "sepolia");
+
+    expect(page.visibleViews()).toEqual(["main"]);
+    expect(page.text("total-value")).toBe("0.0000 SepoliaETH");
+});
+
+// The report of the switch's own save names the network the page already has.
+test("a switch in Settings is not taken a second time when its save is reported", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+    const { get, set } = page.storage.local;
+    const reads = get.mock.calls.length;
+    const writes = set.mock.calls.length;
+
+    const select = page.node("settings-network");
+    select.value = "sepolia";
+    for (const fn of select.listeners.change) await fn();
+    await page.settle();
+    await page.settle();
+
+    expect(get).toHaveBeenCalledTimes(reads + 1);
+    expect(set).toHaveBeenCalledTimes(writes + 1);
+    expect(page.text("flash-msg")).toBe("Switched to Sepolia Testnet.");
+});
+
+// The background saves the switch once the popup has read the stored record
+// and before it listens for changes to it, so the browser tells the page
+// nothing of it. Nor is any later write reported here: Chrome reports none
+// that leaves the record as it was, such as the popup's own save at start-up.
+test("a switch saved while the popup opens, before it listens for one, is followed", async () => {
+    const storage = makeStorageStub({ autistmask: profileOnAddress() });
+    storage.onChanged = { addListener: () => {} };
+    const read = storage.local.get.getMockImplementation();
+    storage.local.get.mockImplementationOnce(async (key) => {
+        const loaded = await read(key);
+        const record = storage.read("autistmask");
+        applyChainSwitchFields(record, "sepolia");
+        storage.write("autistmask", record);
+        return loaded;
+    });
+    const page = await bootPopup(undefined, { storage });
+    await page.settle();
+
+    const { state } = require("../src/shared/state");
+    expect(page.pageErrors).toEqual([]);
+    expect(state.networkId).toBe("sepolia");
+    expect(page.visibleViews()).toEqual(["address"]);
+    expect(page.node("address-balances").innerHTML).toContain("SepoliaETH");
+    expect(page.text("debug-banner")).toBe("[TESTNET]");
+});
+
+// While the popup's follow of the background's switch to Sepolia waits for the
+// lock, the user picks Sepolia in Settings and then Ethereum Mainnet again. The
+// last pick is the network stored, and the last one sites are told of.
+test("a switch in Settings made while a follow waits for the lock is not overwritten by it", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+
+    // Another write holds the lock, so every save of the page waits for it.
+    let releaseLock;
+    const lockHeld = navigator.locks.request(
+        "autistmask",
+        () =>
+            new Promise((resolve) => {
+                releaseLock = resolve;
+            }),
+    );
+    await backgroundSwitch(page, "sepolia");
+    const select = page.node("settings-network");
+    const picks = [];
+    for (const networkId of ["sepolia", "mainnet"]) {
+        select.value = networkId;
+        for (const fn of select.listeners.change) picks.push(fn());
+    }
+    releaseLock();
+    await lockHeld;
+    await Promise.all(picks);
+    await page.settle();
+
+    const { state } = require("../src/shared/state");
+    expect(state.networkId).toBe("mainnet");
+    expect(page.storage.read("autistmask").networkId).toBe("mainnet");
+    expect(page.value("settings-network")).toBe("mainnet");
+    const told = globalThis.chrome.runtime.sendMessage.mock.calls
+        .map(([message]) => message)
+        .filter((message) => message.type === "AUTISTMASK_NETWORK_CHANGED");
+    expect(told.at(-1).chainId).toBe(NETWORKS.mainnet.chainId);
+});
+
+// The popup follows the background's switch to Sepolia, but its own write in
+// that save fails. The user then picks Ethereum Mainnet in Settings, the
+// network the popup was on before: that switch is stored, and only then
+// flashed and sent to sites.
+test("a switch back in Settings after a follow whose write failed is stored", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+    const { set } = page.storage.local;
+    const write = set.getMockImplementation();
+    // The background's write lands; the next, the follow's, fails.
+    set.mockImplementationOnce(write).mockRejectedValueOnce(
+        new Error("quota exceeded"),
+    );
+    await backgroundSwitch(page, "sepolia");
+    const { state } = require("../src/shared/state");
+    expect(state.networkId).toBe("sepolia");
+
+    const select = page.node("settings-network");
+    select.value = "mainnet";
+    for (const fn of select.listeners.change) await fn();
+    await page.settle();
+
+    const stored = page.storage.read("autistmask");
+    expect(stored.networkId).toBe("mainnet");
+    expect(stored.rpcUrl).toBe(NETWORKS.mainnet.defaultRpcUrl);
+    expect(stored.trackedTokens).toEqual([MAINNET_TOKEN]);
+    expect(page.text("flash-msg")).toBe("Switched to Ethereum Mainnet.");
+    const told = globalThis.chrome.runtime.sendMessage.mock.calls
+        .map(([message]) => message)
+        .filter((message) => message.type === "AUTISTMASK_NETWORK_CHANGED");
+    expect(told.at(-1).chainId).toBe(NETWORKS.mainnet.chainId);
+});
+
+// Such as one a newer build wrote, which this build cannot read. Nothing reads
+// or writes the stored record for it: the popup's next save finds it, as
+// before.
+test("a record that names no network is not followed", async () => {
+    const page = await bootOnAddress();
+    const { get, set } = page.storage.local;
+    const reads = get.mock.calls.length;
+
+    await set({
+        autistmask: {
+            schemaVersion: STATE_SCHEMA_VERSION + 1,
+            wallets: [{ type: "hd", name: "Main", addresses: [] }],
+        },
+    });
+    await page.settle();
+
+    expect(get).toHaveBeenCalledTimes(reads);
+    expect(page.visibleViews()).toEqual(["address"]);
+});
+
+// A record that takes the switch from the switched record ends up as that
+// record, balances the background fetched since included.
+test("copyChainSwitchFields() takes every field applyChainSwitchFields() sets", () => {
+    const before = unversionedValidProfile({
+        trackedTokens: [MAINNET_TOKEN],
+        networkTrackedTokens: { sepolia: [SEPOLIA_TOKEN] },
+        networkEndpoints: {
+            sepolia: {
+                rpcUrl: "http://127.0.0.1:8545",
+                blockscoutUrl: "http://127.0.0.1:4000/api/v2",
+            },
+        },
+        lastBalanceRefresh: 1,
+        tokenHolderCache: { [MAINNET_TOKEN.address]: 5000 },
+        fraudContracts: ["0x1111111111111111111111111111111111111111"],
+    });
+    const switched = structuredClone(before);
+    applyChainSwitchFields(switched, "sepolia");
+    switched.wallets[0].addresses[0].balance = "2.0";
+
+    const follower = structuredClone(before);
+    copyChainSwitchFields(follower, switched);
+
+    expect(follower).toEqual(switched);
+});

tests/sendDisplayFloor.test.js

@@ -90,7 +90,7 @@ let approvalDetails = null;
 
 const { makeStorageStub } = require("./support/storageStub");
 global.chrome = {
-    storage: makeStorageStub(),
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
     runtime: {
         connect: () => ({
             postMessage() {},
@@ -220,6 +220,10 @@ async function refreshWith(balanceWei, tokenItems = []) {
     state.wallets = [{ name: "Wallet 1", addresses: [{ address: HOLDER }] }];
     state.selectedWallet = 0;
     state.selectedAddress = 0;
+    // Blockscout is asked only while the stored "Use Blockscout" is on. The
+    // screens save this page's copy of "Use Blockscout" over the stored one. So
+    // the page's copy is turned on here too.
+    state.useBlockscout = true;
     await refreshBalances(
         state.wallets,
         "https://rpc.example.invalid",

tests/sendMax.test.js

@@ -100,7 +100,10 @@ global.fetch = jest.fn(() => {
 });
 
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+    runtime: { sendMessage() {} },
+};
 
 // A stub DOM: every id resolves to a recording element.
 const elements = new Map();
@@ -213,6 +216,10 @@ async function refreshWith(balanceWei, tokenItems = []) {
     ];
     state.selectedWallet = 0;
     state.selectedAddress = 0;
+    // Blockscout is asked only while the stored "Use Blockscout" is on. The
+    // screens save this page's copy of "Use Blockscout" over the stored one. So
+    // the page's copy is turned on here too.
+    state.useBlockscout = true;
     await refreshBalances(
         state.wallets,
         "https://rpc.example.invalid",

tests/sendTokenSelect.test.js

@@ -27,8 +27,12 @@ let select;
 function installStubDocument() {
     select = { innerHTML: "", children: [] };
     select.appendChild = (child) => select.children.push(child);
+    const elements = {
+        "send-token": select,
+        "send-tokens-note": { classList: { toggle: () => {} } },
+    };
     globalThis.document = {
-        getElementById: (id) => (id === "send-token" ? select : null),
+        getElementById: (id) => elements[id] || null,
         createElement: () => ({ value: "", textContent: "" }),
     };
 }

tests/stateRecovery.test.js

@@ -523,13 +523,16 @@ describe("a garbage value in a field the gate does not check", () => {
     });
 
     test("a malformed tokenBalances entry is dropped, and the wallet and its address survive", async () => {
-        const env = await bootPopup(
+        // "Use Blockscout" is on. Otherwise the boot's balance refresh would
-            profileWithTokenBalances([
+        // drop the well-formed entry too, since the user has not tracked its
-                null,
+        // token.
-                42,
+        const profile = profileWithTokenBalances([
-                { address: TOKEN_ADDRESS, symbol: "AAA", balance: "2.0" },
+            null,
-            ]),
+            42,
-        );
+            { address: TOKEN_ADDRESS, symbol: "AAA", balance: "2.0" },
+        ]);
+        profile.useBlockscout = true;
+        const env = await bootPopup(profile);
 
         const stored = env.storage.read("autistmask");
         expect(stored.wallets[0].encryptedSecret).toBe("encrypted-secret-1");

tests/stateWriteLock.test.js

@@ -6,9 +6,8 @@
 // now holds a lock from its read to its write.
 //
 // The popup and the background run here as the real modules over one shared
-// storage stub, and share the lock the way the background and a page outside
+// storage stub, and share the lock the way the background and its pages share
-// a Firefox private window share the browser's
+// the browser's (tests/support/navigatorLocks.js).
-// (tests/support/navigatorLocks.js).
 
 const { makeStorageStub } = require("./support/storageStub");
 

tests/support/navigatorLocks.js

@@ -4,9 +4,8 @@
 // the callback settles, whether it resolved or rejected. That is what the
 // browser's own does for the one call the extension makes,
 // `navigator.locks.request(name, callback)`. Every module a test file loads
-// shares it, as the extension's background and its pages share the browser's,
+// shares it, as the extension's background and its pages share the browser's
-// except a page in a Firefox private window (README, "Stored state and its
+// (README, "Stored state and its version").
-// version").
 //
 // Run before each test file by `setupFiles` in package.json.
 

tests/support/popupBoot.js

@@ -283,6 +283,8 @@ async function bootPopup(stored, options) {
     jest.doMock("../../src/shared/balances", () => ({
         fetchTokenBalances: jest.fn(async () => []),
         refreshBalances: jest.fn(async () => {}),
+        dropUntrackedTokens: jest.requireActual("../../src/shared/balances")
+            .dropUntrackedTokens,
         lookupTokenInfo: jest.fn(async () => null),
         getProvider: () => ({}),
         scanForAddresses: jest.fn(async () => ({
@@ -311,7 +313,7 @@ async function bootPopup(stored, options) {
     const windowListeners = {};
 
     globalThis.chrome = {
-        storage: { local: storage.local },
+        storage: { local: storage.local, onChanged: storage.onChanged },
         runtime: {
             sendMessage: jest.fn(async () => ({})),
             getURL: (p) => "chrome-extension://autistmask/" + p,

tests/support/storageStub.js

@@ -18,7 +18,9 @@
 // a storage stub by hand.
 
 // One storage area: get, set and remove over its own store, cloning both ways.
-function makeArea(store, tick) {
+// `changed` is handed what each set or remove changed, in the shape
+// storage.onChanged reports it.
+function makeArea(store, tick, changed) {
     const get = jest.fn(async (key) => {
         tick();
         if (key === undefined || key === null) return structuredClone(store);
@@ -34,14 +36,25 @@ function makeArea(store, tick) {
 
     const set = jest.fn(async (items) => {
         tick();
+        const changes = {};
         for (const k of Object.keys(items)) {
+            changes[k] = structuredClone({
+                oldValue: store[k],
+                newValue: items[k],
+            });
             store[k] = structuredClone(items[k]);
         }
+        changed(changes);
     });
 
     const remove = jest.fn(async (key) => {
         tick();
-        for (const k of Array.isArray(key) ? key : [key]) delete store[k];
+        const changes = {};
+        for (const k of Array.isArray(key) ? key : [key]) {
+            changes[k] = { oldValue: store[k] };
+            delete store[k];
+        }
+        changed(changes);
     });
 
     return { get, set, remove };
@@ -54,12 +67,22 @@ function makeArea(store, tick) {
 function makeStorageStub(initial, onOp) {
     const store = initial ? structuredClone(initial) : {};
     const tick = onOp || (() => {});
-    const local = makeArea(store, tick);
+    // storage.onChanged: after a set or remove has finished, every listener is
+    // called with what it changed and the area's name, as the browser calls
+    // them for a write by any page or the background.
+    const listeners = [];
+    const announce = (areaName) => (changes) => {
+        Promise.resolve().then(() => {
+            for (const fn of listeners) fn(structuredClone(changes), areaName);
+        });
+    };
+    const local = makeArea(store, tick, announce("local"));
 
     return {
         // Drop this straight in as chrome.storage.
         local,
-        session: makeArea({}, tick),
+        session: makeArea({}, tick, announce("session")),
+        onChanged: { addListener: (fn) => listeners.push(fn) },
         get: local.get,
         set: local.set,
         remove: local.remove,
@@ -71,7 +94,9 @@ function makeStorageStub(initial, onOp) {
                 ? structuredClone(store)
                 : structuredClone(store[key]),
         // Seed or replace a record without going through the module under
-        // test — for standing in as "another page wrote this".
+        // test — for standing in as "another page wrote this". Nothing is
+        // announced to storage.onChanged, so it also stands in for the time
+        // before the browser tells this page of such a write.
         write: (key, value) => {
             store[key] = structuredClone(value);
         },

tests/symbolSpoof.test.js

@@ -52,8 +52,14 @@ jest.mock("../src/shared/log", () => ({
 global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 global.chrome = {
-    storage: { local: { get: async () => ({}), set: async () => {} } },
+    storage: {
+        local: {
+            get: async () => ({ autistmask: { useBlockscout: true } }),
+            set: async () => {},
+        },
+    },
 };
 
 const { isSpoofedSymbol } = require("../src/shared/symbolSpoof");
@@ -485,8 +491,12 @@ describe("surface 2: the Send token selector", () => {
     function render(tokenBalances) {
         select = { innerHTML: "", children: [] };
         select.appendChild = (child) => select.children.push(child);
+        const elements = {
+            "send-token": select,
+            "send-tokens-note": { classList: { toggle: () => {} } },
+        };
         globalThis.document = {
-            getElementById: (id) => (id === "send-token" ? select : null),
+            getElementById: (id) => elements[id] || null,
             createElement: () => ({ value: "", textContent: "" }),
         };
         renderSendTokenSelect({

tests/timestampDisplay.test.js

@@ -134,6 +134,8 @@ beforeEach(() => {
     state.selectedWallet = 0;
     state.selectedAddress = 0;
     state.selectedToken = "ETH";
+    // The history is Blockscout's.
+    state.useBlockscout = true;
 });
 
 describe.each([

tests/tokenTransferDetail.test.js

@@ -38,8 +38,14 @@ jest.mock("../src/shared/log", () => ({
     isDebug: () => false,
 }));
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 globalThis.chrome = {
-    storage: { local: { get: async () => ({}), set: async () => {} } },
+    storage: {
+        local: {
+            get: async () => ({ autistmask: { useBlockscout: true } }),
+            set: async () => {},
+        },
+    },
 };
 
 const { state } = require("../src/shared/state");
@@ -158,6 +164,7 @@ beforeEach(() => {
     globalThis.document = makeDocument();
     globalThis.window = { location: { search: "" } };
     state.blockscoutUrl = EXPLORER;
+    state.useBlockscout = true;
     state.networkEndpoints = {};
     state.wallets = [
         {

tests/trackedTokenBalances.test.js

@@ -0,0 +1,309 @@
+// The balance of each token the user tracks is read with balanceOf through the
+// RPC endpoint, for every address. Blockscout's answer gives a tracked token its
+// holder count and decimals, and adds the tokens the user has not tracked
+// (https://git.eeqj.de/sneak/AutistMask/issues/669).
+//
+// The real refreshBalances() runs against a fake JSON-RPC node, answered
+// through ethers' own request hook, and a fake Blockscout, answered through
+// fetch().
+
+const { AbiCoder, FetchRequest } = require("ethers");
+const { refreshBalances } = require("../src/shared/balances");
+const { makeStorageStub } = require("./support/storageStub");
+
+// Blockscout is asked only while the stored "Use Blockscout" is on.
+globalThis.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+};
+
+const RPC_URL = "https://rpc.example.invalid";
+const EXPLORER_URL = "https://explorer.example.invalid/api/v2";
+const FIRST = "0x1111111111111111111111111111111111111111";
+const SECOND = "0x2222222222222222222222222222222222222222";
+
+// A token the user tracks, outside the bundled list, at 6 decimals.
+const TOKEN = "0x7777777777777777777777777777777777777777";
+const TRACKED = {
+    address: TOKEN,
+    symbol: "TRK",
+    name: "Tracked Token",
+    decimals: 6,
+};
+
+// USDC, from the bundled list, which the user does not track.
+const USDC = "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48";
+// Neither on the bundled list nor tracked.
+const OTHER = "0x8888888888888888888888888888888888888888";
+
+const ZERO_WORD = "0x" + "0".repeat(64);
+const BALANCE_OF = "0x70a08231";
+
+// What balanceOf answers, by token contract and then by holder. A pair that is
+// not here makes balanceOf fail.
+let holdings;
+// What Blockscout answers for every address; null makes the request fail.
+let explorerRows;
+let logged;
+
+// One JSON-RPC answer. A call that is not balanceOf is the ENS reverse lookup,
+// answered with no resolver, so no name.
+function reply(req) {
+    const envelope = { jsonrpc: "2.0", id: req.id };
+    if (req.method === "eth_getBalance") {
+        return { ...envelope, result: "0x0" };
+    }
+    if (req.method !== "eth_call") {
+        return {
+            ...envelope,
+            error: { code: -32601, message: "method not found" },
+        };
+    }
+    const { to, data } = req.params[0];
+    if (!data.startsWith(BALANCE_OF)) return { ...envelope, result: ZERO_WORD };
+    const holder = "0x" + data.slice(-40);
+    const amount = (holdings[to.toLowerCase()] || {})[holder];
+    if (amount === undefined) {
+        return {
+            ...envelope,
+            error: { code: -32000, message: "fixture: balanceOf failed" },
+        };
+    }
+    return {
+        ...envelope,
+        result: AbiCoder.defaultAbiCoder().encode(["uint256"], [amount]),
+    };
+}
+
+const realFetch = globalThis.fetch;
+
+beforeEach(() => {
+    holdings = {};
+    explorerRows = null;
+    logged = [];
+    jest.spyOn(console, "error").mockImplementation((...args) => {
+        logged.push(args.map(String).join(" "));
+    });
+    FetchRequest.registerGetUrl(async (req) => {
+        const body = JSON.parse(Buffer.from(req.body).toString("utf8"));
+        const answer = Array.isArray(body) ? body.map(reply) : reply(body);
+        return {
+            statusCode: 200,
+            statusMessage: "OK",
+            headers: { "content-type": "application/json" },
+            body: Buffer.from(JSON.stringify(answer)),
+        };
+    });
+    globalThis.fetch = jest.fn(async () => {
+        if (explorerRows === null) throw new TypeError("Failed to fetch");
+        return { ok: true, status: 200, json: async () => explorerRows };
+    });
+});
+
+afterEach(() => {
+    FetchRequest.registerGetUrl(FetchRequest.createGetUrlFunc());
+    globalThis.fetch = realFetch;
+    jest.restoreAllMocks();
+});
+
+// One Blockscout token-balances row.
+function explorerRow(address, symbol, value, holders = "50000") {
+    return {
+        value: String(value),
+        token: {
+            type: "ERC-20",
+            address_hash: address,
+            symbol: symbol,
+            name: symbol,
+            decimals: "6",
+            holders_count: holders,
+        },
+    };
+}
+
+// The row refreshBalances() writes for TOKEN from a balanceOf answer, with the
+// decimals and holder count Blockscout reported for it, if any.
+function trackedRow(balance, decimals = null, holders = null) {
+    return {
+        address: TOKEN,
+        name: "Tracked Token",
+        symbol: "TRK",
+        decimals: decimals,
+        balance: balance,
+        holders: holders,
+    };
+}
+
+async function refresh(addresses, trackedTokens) {
+    await refreshBalances(
+        [{ addresses }],
+        RPC_URL,
+        EXPLORER_URL,
+        trackedTokens,
+        "mainnet",
+        new AbortController().signal,
+    );
+    return addresses;
+}
+
+test("with Blockscout failing, a tracked token's balance is read through the RPC endpoint for every address", async () => {
+    holdings[TOKEN] = { [FIRST]: 1234500000n, [SECOND]: 1n };
+    const [first, second] = await refresh(
+        [
+            { address: FIRST, tokenBalances: [] },
+            { address: SECOND, tokenBalances: [] },
+        ],
+        [TRACKED],
+    );
+    expect(first.tokenBalances).toEqual([trackedRow("1234.5")]);
+    // Exact, never cut: one base unit is not zero.
+    expect(second.tokenBalances).toEqual([trackedRow("0.000001")]);
+});
+
+test("with Blockscout failing, the untracked rows from before stay", async () => {
+    holdings[TOKEN] = { [FIRST]: 2000000n };
+    const usdc = {
+        address: USDC,
+        name: "USD Coin",
+        symbol: "USDC",
+        decimals: 6,
+        balance: "5.0",
+        holders: 50000,
+    };
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [usdc] }],
+        [TRACKED],
+    );
+    expect(first.tokenBalances).toEqual([trackedRow("2.0"), usdc]);
+});
+
+test("a tracked token Blockscout also reports shows the RPC figure, and an untracked one is admitted as before", async () => {
+    holdings[TOKEN] = { [FIRST]: 2000000n };
+    explorerRows = [
+        explorerRow(TOKEN, "TRK", 9000000),
+        explorerRow(USDC, "USDC", 5000000),
+        // Too few holders, and neither on the bundled list nor tracked.
+        explorerRow(OTHER, "SPAM", 5000000, "10"),
+        // A known symbol from a contract it does not belong to.
+        explorerRow(OTHER, "USDC", 5000000),
+    ];
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [TRACKED],
+    );
+    expect(first.tokenBalances).toEqual([
+        trackedRow("2.0", 6, 50000),
+        {
+            address: USDC,
+            name: "USDC",
+            symbol: "USDC",
+            decimals: 6,
+            balance: "5.0",
+            holders: 50000,
+        },
+    ]);
+});
+
+test("a tracked token's entry carries the holder count and decimals Blockscout reports for it", async () => {
+    holdings[TOKEN] = { [FIRST]: 2000000n };
+    // Fewer holders than "Hide tokens with fewer than 1,000 holders" lets
+    // through to Send's token list.
+    explorerRows = [explorerRow(TOKEN, "TRK", 9000000, "10")];
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [TRACKED],
+    );
+    expect(first.tokenBalances).toEqual([trackedRow("2.0", 6, 10)]);
+});
+
+test("while Blockscout fails, a tracked token keeps the holder count and decimals of its entry from before", async () => {
+    holdings[TOKEN] = { [FIRST]: 2000000n };
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [trackedRow("7.0", 6, 10)] }],
+        [TRACKED],
+    );
+    expect(first.tokenBalances).toEqual([trackedRow("2.0", 6, 10)]);
+});
+
+test("a failed balanceOf keeps the token's entry from before, and is logged", async () => {
+    explorerRows = [explorerRow(TOKEN, "TRK", 9000000)];
+    const before = trackedRow("7.0", 6, 50000);
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [before] }],
+        [TRACKED],
+    );
+    expect(first.tokenBalances).toEqual([before]);
+    expect(logged.some((line) => line.includes("token balance failed"))).toBe(
+        true,
+    );
+});
+
+test("a failed balanceOf with no entry from before takes Blockscout's entry from this refresh", async () => {
+    // balanceOf fails at FIRST and answers at SECOND.
+    holdings[TOKEN] = { [SECOND]: 2000000n };
+    explorerRows = [explorerRow(TOKEN, "TRK", 9000000)];
+    const [first, second] = await refresh(
+        [
+            { address: FIRST, tokenBalances: [] },
+            { address: SECOND, tokenBalances: [] },
+        ],
+        [TRACKED],
+    );
+    expect(first.tokenBalances).toEqual([
+        {
+            address: TOKEN,
+            name: "TRK",
+            symbol: "TRK",
+            decimals: 6,
+            balance: "9.0",
+            holders: 50000,
+        },
+    ]);
+    // Where balanceOf answers, its figure stands.
+    expect(second.tokenBalances).toEqual([trackedRow("2.0", 6, 50000)]);
+});
+
+test("a balance of zero read through the RPC endpoint replaces the previous figure", async () => {
+    holdings[TOKEN] = { [FIRST]: 0n };
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [trackedRow("7.0")] }],
+        [TRACKED],
+    );
+    expect(first.tokenBalances).toEqual([]);
+});
+
+test("a tracked token whose scale nothing knows gets no quantity, not a zero", async () => {
+    holdings[TOKEN] = { [FIRST]: 5n };
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [{ ...TRACKED, decimals: null }],
+    );
+    expect(first.tokenBalances).toEqual([trackedRow(null)]);
+});
+
+test("a tracked token whose scale only Blockscout reports is stated at that scale", async () => {
+    holdings[TOKEN] = { [FIRST]: 2000000n };
+    explorerRows = [explorerRow(TOKEN, "TRK", 9000000)];
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [{ ...TRACKED, decimals: null }],
+    );
+    expect(first.tokenBalances).toEqual([trackedRow("2.0", 6, 50000)]);
+});
+
+test("a tracked token wearing a known symbol from another contract is not listed", async () => {
+    holdings[OTHER] = { [FIRST]: 5000000n };
+    // Its entry from before goes too, although Blockscout fails.
+    const before = {
+        address: OTHER,
+        name: "Fake",
+        symbol: "USDC",
+        decimals: 6,
+        balance: "5.0",
+        holders: 50000,
+    };
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [before] }],
+        [{ address: OTHER, symbol: "USDC", name: "Fake", decimals: 6 }],
+    );
+    expect(first.tokenBalances).toEqual([]);
+});

tests/trackedTokensPerNetwork.test.js

@@ -161,6 +161,7 @@ test("a token added by contract address on Sepolia is tracked on Sepolia only",
     );
     expect(stored().trackedTokens).toEqual([SEPOLIA_TOKEN]);
 
+    await boot.click("btn-settings");
     await chooseNetwork(boot, "mainnet");
     expect(stored().networkId).toBe("mainnet");
     expect(stored().trackedTokens).toEqual([MAINNET_TOKEN]);
@@ -286,6 +287,7 @@ describe("Back after a switch from the Settings gear", () => {
                 currentView: "confirm-tx",
                 selectedWallet: 0,
                 selectedAddress: 0,
+                checkRecipientsOnEtherscan: true,
                 viewData: {
                     pendingTx: {
                         token: "ETH",

tests/transactionListCancelled.test.js

@@ -125,6 +125,8 @@ beforeEach(() => {
     state.selectedWallet = 0;
     state.selectedAddress = 0;
     state.selectedToken = "ETH";
+    // The history is Blockscout's.
+    state.useBlockscout = true;
 });
 
 afterEach(() => {

tests/transactions.test.js

@@ -1215,6 +1215,8 @@ function respondWith(txItems, tokenTransferItems) {
 describe("fetchRecentTransactions merge and dedup", () => {
     beforeEach(() => {
         debugFetch.mockReset();
+        // Blockscout is asked only while the stored "Use Blockscout" is on.
+        global.chrome.storage.write("autistmask", { useBlockscout: true });
     });
 
     test("queries only the two Blockscout endpoints for the address", async () => {

tests/uniswapRecipient.test.js

@@ -42,8 +42,14 @@ jest.mock("../src/shared/log", () => ({
     isDebug: () => false,
 }));
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 globalThis.chrome = {
-    storage: { local: { get: async () => ({}), set: async () => {} } },
+    storage: {
+        local: {
+            get: async () => ({ autistmask: { useBlockscout: true } }),
+            set: async () => {},
+        },
+    },
 };
 
 const uniswap = require("../src/shared/uniswap");
@@ -1332,6 +1338,10 @@ describe("any token left in the router is not received", () => {
                 ),
             ),
             left: tokenLine(WETH, "WETH"),
+            // The second swap action spends 1 USDC of what the first buys,
+            // so the step states no minimum
+            // (https://git.eeqj.de/sneak/AutistMask/issues/574).
+            noMin: true,
         },
         {
             kind: "a WRAP_ETH of 1 ETH into the router, then a V4 SETTLE of OPEN_DELTA from the router before the swap, which the user settles",
@@ -1432,15 +1442,24 @@ describe("any token left in the router is not received", () => {
             ),
             left: { label: "Token moved into the router", value: "ETH" },
         },
-    ])("$kind", ({ data, left, spent, unread }) => {
+    ])("$kind", ({ data, left, spent, unread, noMin }) => {
         const result = decode(data);
         expect(labels(result)).toEqual([
             "Protocol",
             "Token In",
             // A later step whose SETTLE or SETTLE_ALL the decoder cannot read
             // may take anything from the sender: one line says so, in place
-            // of the Amount line (https://git.eeqj.de/sneak/AutistMask/issues/625).
+            // of the Amount line (https://git.eeqj.de/sneak/AutistMask/issues/625),
-            unread ? "Moved from the sender" : "Amount",
+            // after the lines the WRAP_ETH's 1 ETH then gets
+            // (https://git.eeqj.de/sneak/AutistMask/issues/659).
+            ...(unread
+                ? [
+                      "Moved from the sender",
+                      "Token moved",
+                      "Moved to",
+                      "Moved from the sender",
+                  ]
+                : ["Amount"]),
             // A later swap step the user pays for spends `spent` of a token
             // other than Token In.
             ...(spent
@@ -1449,7 +1468,7 @@ describe("any token left in the router is not received", () => {
             "Token Out",
             "Paid to",
             "Token moved into the router",
-            "Min. paid out",
+            ...(noMin ? [] : ["Min. paid out"]),
             "Steps",
             "Deadline",
         ]);
@@ -1457,13 +1476,17 @@ describe("any token left in the router is not received", () => {
             expect(detail(result, "Moved from the sender").value).toBe(spent);
         }
         if (unread) {
-            expect(detail(result, "Moved from the sender").value).toBe(
+            expect(
-                UNDECODED,
+                result.details
-            );
+                    .filter((d) => d.label === "Moved from the sender")
+                    .map((d) => d.value),
+            ).toEqual(["1.0000 ETH", UNDECODED]);
         }
         expect(paidTo(result)).toEqual([STAYS_IN_ROUTER]);
         expect(detail(result, "Token moved into the router")).toEqual(left);
-        expect(detail(result, "Min. paid out").value).toBe("1990.0000 USDC");
+        expect(detail(result, "Min. paid out")?.value).toBe(
+            noMin ? undefined : "1990.0000 USDC",
+        );
     });
 
     // Uniswap's own routes: a swap paid in ETH wraps into the router what its
@@ -2791,26 +2814,37 @@ describe("the allow-revert flag", () => {
     });
 
     // Only the routers from UniversalRouterV2 on let a PERMIT2_PERMIT fail.
+    // The permit's spender is the router at ROUTER, which on every other
+    // router is an allowance to another spender, so the minimum reads
+    // Min. paid out there.
     test.each([
-        { router: "UniversalRouterV1", address: ROUTER_V1, mark: "" },
+        {
+            router: "UniversalRouterV1",
+            address: ROUTER_V1,
+            mark: "",
+            minimum: "Min. paid out",
+        },
         {
             router: "UniversalRouterV1_2_V2Support",
             address: ROUTER_V1_2,
             mark: "",
+            minimum: "Min. paid out",
         },
         {
             router: "UniversalRouterV2",
             address: ROUTER,
             mark: " (allowed to fail)",
+            minimum: "Min. received",
         },
         {
             router: "UniversalRouterV2_1_2",
             address: ROUTER_V2_1_2,
             mark: " (allowed to fail)",
+            minimum: "Min. paid out",
         },
     ])(
-        "on $router, a PERMIT2_PERMIT with the flag is listed as 'Permit2 Permit$mark', and the swap reads as without the flag",
+        "on $router, a PERMIT2_PERMIT with the flag is listed as 'Permit2 Permit$mark', and the swap's lines read as without the flag",
-        ({ address, mark }) => {
+        ({ address, mark, minimum }) => {
             const steps = [
                 permit2Permit(USDT, USDT_2000),
                 swapToWeth(MSG_SENDER),
@@ -2824,10 +2858,25 @@ describe("the allow-revert flag", () => {
             expect(detail(withFlag, "Steps").value).toBe(
                 "Permit2 Permit" + mark + " → V3 Swap (Exact In)",
             );
-            const withoutSteps = (r) =>
+            // The permit names the router at ROUTER as its spender, so its
-                r.details.filter((d) => d.label !== "Steps");
+            // amount stands as the Amount figure only there, and only without
-            expect(withoutSteps(withFlag)).toEqual(withoutSteps(plain));
+            // the flag. With the flag it stands on no router and gets lines
-            expect(detail(withFlag, "Min. received").value).toBe("1.0000 WETH");
+            // of its own, and the swap step names Token In: the same token,
+            // its address written the same way.
+            const permitLines = [
+                "Permit2 allowance",
+                "Allowance token",
+                "Allowance spender",
+            ];
+            const swapLines = (r) =>
+                r.details.filter(
+                    (d) => !["Steps", ...permitLines].includes(d.label),
+                );
+            expect(swapLines(withFlag)).toEqual(swapLines(plain));
+            expect(
+                labels(withFlag).filter((l) => permitLines.includes(l)),
+            ).toEqual(permitLines);
+            expect(detail(withFlag, minimum).value).toBe("1.0000 WETH");
         },
     );
 
@@ -3413,6 +3462,7 @@ async function showDetail(data) {
     globalThis.window = { location: { search: "" } };
     state.networkId = "mainnet";
     state.blockscoutUrl = "https://explorer.example/api/v2";
+    state.useBlockscout = true;
     state.viewData = {};
     state.viewStack = [];
     state.currentView = null;

tests/uniswapRouterAddress.test.js

@@ -34,8 +34,14 @@ jest.mock("../src/shared/log", () => ({
     isDebug: () => false,
 }));
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 globalThis.chrome = {
-    storage: { local: { get: async () => ({}), set: async () => {} } },
+    storage: {
+        local: {
+            get: async () => ({ autistmask: { useBlockscout: true } }),
+            set: async () => {},
+        },
+    },
 };
 
 const { state } = require("../src/shared/state");
@@ -208,6 +214,7 @@ async function showDetail(row, activeNetworkId) {
     globalThis.window = { location: { search: "" } };
     state.networkId = activeNetworkId;
     state.blockscoutUrl = "https://explorer.example/api/v2";
+    state.useBlockscout = true;
     state.viewData = {};
     state.viewStack = [];
     state.currentView = null;

tests/uniswapUnknownDecimals.test.js

@@ -90,6 +90,9 @@ function swapDetail(data, label) {
 beforeEach(() => {
     state.trackedTokens = [];
     state.wallets = [];
+    // The approval screen reads the explorer's report only while "Use
+    // Blockscout" is on.
+    state.useBlockscout = true;
 });
 
 describe("a swap of a token outside the bundled list", () => {

tests/unknownScaleSend.test.js

@@ -72,8 +72,12 @@ global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+    runtime: { sendMessage() {} },
+};
 
 // A stub DOM. Every id in index.html that these two views touch resolves to a
 // fresh recording element; nothing here depends on layout, only on what the
@@ -268,6 +272,9 @@ beforeEach(() => {
     state.fraudContracts = [];
     state.hideLowHolderTokens = false;
     state.currentView = null;
+    // The screens save this page's copy of "Use Blockscout" over the stored
+    // one. So the page's copy is turned on here too.
+    state.useBlockscout = true;
 });
 
 describe("the Send screen resolves the scale rather than reading the stored one", () => {