fix: the bundled token list names tokens on Ethereum Mainnet only (closes #632 )

bundledToken(address, chainId) in tokenList.js answers only for Ethereum Mainnet's chain id. Every reader of TOKEN_BY_ADDRESS now goes through it, with the chain id of the transaction, balance or history entry it draws. The token sources the screens build carry that chain id. The Uniswap decoder sets the transaction's chain id on them. fetchTokenBalances() takes the chain id of the network it asks about. isSpoofedSymbol() takes the chain id of the token's network. It checks the bundled list's symbols only on Ethereum Mainnet. The native asset's labels stay reserved on every network. Eighteen existing tests and three shared test helpers read the bundled list without naming a network. Each now names Ethereum Mainnet. Model: opus-5-5
2026-10-27 20:14:25 +00:00
24 changed files with 693 additions and 259 deletions
@@ -1188,11 +1188,12 @@ The wallet takes the `decimals` from these sources, in this order
  "Use Blockscout" is on (`tokenSourcesByChainId()` in
  `src/popup/views/helpers.js`).

-The token's name comes from the same sources. While "Use Blockscout" is off, a
-token gets a line under it when the bundled list and the tracked tokens lack its
-name or decimals. The line says "Blockscout's report of your balances is not
-used to name this token, because "Use Blockscout" is off in Settings." These
-screens show the line:
+The token's name comes from the same sources. The bundled token list is used
+only for a token on Ethereum Mainnet. While "Use Blockscout" is off, a token
+gets a line under it when the bundled list and the tracked tokens lack its name
+or decimals. The line says "Blockscout's report of your balances is not used to
+name this token, because "Use Blockscout" is off in Settings." These screens
+show the line:

 - TxApproval and SignApproval
 - WaitTx, SuccessTx and ErrorTx, which follow TxApproval
@@ -1473,20 +1474,20 @@ tracked.

 A tracked token is shown when its balance is nonzero, and any other ERC-20 when
 its balance is nonzero and it is in the bundled known-token list or has 1,000 or
-more holders. A token claiming a symbol from the bundled list from any other
-contract address is always dropped, tracked or not, and so is any token claiming
-a symbol that belongs to the native asset and therefore has no legitimate
-contract at all (`"ETH"`, and every network's `nativeCurrency`, such as
-`"SepoliaETH"`, on every network). That filter is unconditional — the "Hide
-tokens with fewer than 1,000 holders" setting governs the transaction history
-and the send-screen token selector, not this list. A token's holder count is
-unknown when the explorer reports none, or reports anything other than a whole
-number written in digits alone, such as `1,000` or `1e3` (`parseHoldersCount()`
-in `src/shared/holders.js`). This list does not take an unknown count as 1,000
-or more, so such a token is shown only when it is on the bundled list or
-tracked. Every nonzero holding of a token shown is stored exactly, however
-small, but a holding below 0.000001 is left out of the balance lists, the
-send-screen token selector, the address total and the remove-address warning
+more holders. On Ethereum Mainnet, a token that claims a bundled token's symbol
+from another contract is always dropped, tracked or not. On every network, a
+token claiming a label of the native asset is always dropped. Those labels are
+`"ETH"` and each network's `nativeCurrency`, such as `"SepoliaETH"`. The balance
+list applies all three rules whatever the settings say. The "Hide tokens with
+fewer than 1,000 holders" setting governs only the transaction history and the
+send-screen token selector. A token's holder count is unknown when the explorer
+reports none, or reports anything other than a whole number written in digits
+alone, such as `1,000` or `1e3` (`parseHoldersCount()` in
+`src/shared/holders.js`). This list does not take an unknown count as 1,000 or
+more, so such a token is shown only when it is on the bundled list or tracked.
+Every nonzero holding of a token shown is stored exactly, however small, but a
+holding below 0.000001 is left out of the balance lists, the send-screen token
+selector, the address total and the remove-address warning
 (`isBelowOneMillionth()` in `src/shared/amountDisplay.js`). The Send and
 confirmation screens show it when its token is the one being sent. Tracked
 tokens with a zero balance are listed as well while "Show tracked tokens with
@@ -3198,26 +3199,25 @@ indexes it as a real token transfer.
  Ethereum mainnet ERC-20s taken from the CoinGecko API, with decimals verified
  on-chain and addresses EIP-55 checksummed; `TOKENS` in
  `src/shared/tokenList.js` is the authoritative set. It is bundled at build
-  time and only changes when that file is regenerated. Any token transfer
-  claiming a symbol from this list (e.g. "ETH", "USDT", "USDC") but originating
-  from an unrecognized contract address is identified as a spoof and filtered
-  from display. The fake "Ethereum" token in the attack above used symbol "ETH"
-  from contract `0xD05339f9Ea5ab9d9F03B9d57F671d2abD1F55c82`, which does not
-  match the known WETH contract — so it would be caught by this check. Detecting
-  a spoof is also what adds a contract to the fraud contract blocklist below;
-  that is the only thing that populates it. In the transaction history the check
-  is the "Hide fake tokens impersonating a known symbol" setting, on by default;
-  with it off, spoofed transfers are shown and no new blocklist entries are
-  learned from them. The send-screen token selector and the balance list apply
-  the same check unconditionally, because they decide which tokens the user can
-  act on and what the user believes they own rather than what the history
-  displays. All three surfaces read the rule from `src/shared/symbolSpoof.js`,
-  so they cannot answer the question differently. A symbol the list maps to no
-  contract at all — the native asset's labels: `"ETH"` and every network's
-  `nativeCurrency`, such as `"SepoliaETH"`, on every network — may be borne by
-  no contract, so every ERC-20 claiming it is a spoof on all three. The user's
-  real ETH balance is not an ERC-20 and is read over RPC, so the rule never sees
-  it.
+  time and only changes when that file is regenerated. On Ethereum Mainnet, a
+  token that claims a symbol from this list, such as "USDT" or "USDC", is a
+  spoof unless its contract is the listed one. The wallet hides it. The fake
+  "Ethereum" token in the attack above used symbol "ETH" from contract
+  `0xD05339f9Ea5ab9d9F03B9d57F671d2abD1F55c82`. No contract may bear "ETH", so
+  that token is a spoof. Detecting a spoof is also what adds a contract to the
+  fraud contract blocklist below; that is the only thing that populates it. In
+  the transaction history the check is the "Hide fake tokens impersonating a
+  known symbol" setting, on by default; with it off, spoofed transfers are shown
+  and no new blocklist entries are learned from them. The send-screen token
+  selector and the balance list apply the same check unconditionally, because
+  they decide which tokens the user can act on and what the user believes they
+  own rather than what the history displays. All three surfaces read the rule
+  from `src/shared/symbolSpoof.js`, so they cannot answer the question
+  differently. A symbol the list maps to no contract at all — the native asset's
+  labels: `"ETH"` and every network's `nativeCurrency`, such as `"SepoliaETH"`,
+  on every network — may be borne by no contract, so every ERC-20 claiming it is
+  a spoof on all three. The user's real ETH balance is not an ERC-20 and is read
+  over RPC, so the rule never sees it.

 - **Low-holder token filtering**: Token transfers from ERC-20 contracts with
  fewer than 1,000 holders are hidden from transaction history by default.
@@ -377,13 +377,15 @@ point-in-time snapshot of the highest-market-cap Ethereum mainnet ERC-20s, fixed
 at build time and updated only when a new release ships a newer snapshot. If a
 transaction or balance claims to involve a known symbol (like "ETH" or "USDT")
 but comes from an unrecognized contract, it is identified as a spoof and hidden.
-In your transaction history this is the "Hide fake tokens impersonating a known
-symbol" setting, which you can switch off; doing so also stops new entries being
-added to the fraud contract blocklist below, since detecting a spoof is what
-fills it. The send token list always applies the check. Your balances apply it
-too, with one exception: a token claiming the symbol "ETH" is not filtered
-there, so a fake "ETH" token can still show up in your balance list even though
-it is hidden from your transaction history and from the send token list.
+On Sepolia, only "ETH" and "SepoliaETH" count as known symbols, because the
+bundled list holds Ethereum Mainnet tokens. In your transaction history the
+check is the "Hide fake tokens impersonating a known symbol" setting, which you
+can switch off; doing so also stops new entries being added to the fraud
+contract blocklist below, since detecting a spoof is what fills it. The send
+token list always applies the check. Your balances apply it too, with one
+exception: a token claiming the symbol "ETH" is not filtered there, so a fake
+"ETH" token can still show up in your balance list even though it is hidden from
+your transaction history and from the send token list.

 **Low-holder token filtering.** Tokens with fewer than 1,000 holders are hidden
 from transaction history and the send token list, and are left out of your
@@ -22,7 +22,7 @@ const {
    timeAgo,
 } = require("./helpers");
 const { state, saveState, currentNetwork } = require("../../shared/state");
-const { TOKEN_BY_ADDRESS, resolveSymbol } = require("../../shared/tokenList");
+const { bundledToken, resolveSymbol } = require("../../shared/tokenList");
 const { formatUsd, getPrice } = require("../../shared/prices");
 const {
    fetchRecentTransactions,
@@ -52,7 +52,8 @@ function show() {

    // Determine token symbol and balance
    let symbol, amount, price;
-    const knownToken = TOKEN_BY_ADDRESS.get(tokenId.toLowerCase());
+    const chainId = currentNetwork().chainId;
+    const knownToken = bundledToken(tokenId, chainId);
    if (tokenId === "ETH") {
        symbol = nativeCurrency();
        amount = parseFloat(addr.balance || "0");
@@ -65,6 +66,7 @@ function show() {
            tokenId,
            addr.tokenBalances,
            state.trackedTokens,
+            chainId,
        );
        // null when the scale is unknown: no quantity to show, and none to
        // price. balanceLine() states that rather than printing 0.0000.
@@ -313,14 +313,17 @@ function nativeCurrency() {
 // 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();
+    const chainIdOrActive = chainId || currentNetwork().chainId;
+    const net = networkByChainId(chainIdOrActive);
    if (net && net.id === state.networkId) {
        return {
+            chainId: chainIdOrActive,
            trackedTokens: state.trackedTokens,
            wallets: state.useBlockscout ? state.wallets : [],
        };
    }
    return {
+        chainId: chainIdOrActive,
        trackedTokens: (net && state.networkTrackedTokens[net.id]) || [],
        wallets: [],
    };
@@ -351,7 +354,7 @@ function blockscoutOffTokenNoteHtml(token, chainId) {

 // The symbol shown for a token line, from these sources in order:
 //
-// - the bundled list
+// - the bundled list, for a token on Ethereum Mainnet
 // - the tokens the user tracks
 // - the explorer's report, while "Use Blockscout" is on
 //
@@ -12,7 +12,7 @@ const {
    goBack,
    tokenSourcesByChainId,
 } = require("./helpers");
-const { state, currentAddress } = require("../../shared/state");
+const { state, currentAddress, currentNetwork } = require("../../shared/state");
 let ctx;
 const { getProvider } = require("../../shared/balances");
 const { resolveTokenDecimals } = require("../../shared/approvalAmount");
@@ -154,7 +154,9 @@ function renderSendTokenSelect(addr) {
        // out. Its token's own screen can still send it: there
        // state.selectedToken picks the token, not this list.
        if (isBelowOneMillionth(t.balance)) continue;
-        if (isSpoofedSymbol(t.symbol, t.address)) continue;
+        if (isSpoofedSymbol(t.symbol, t.address, currentNetwork().chainId)) {
+            continue;
+        }
        if (fraudSet.has(t.address.toLowerCase())) continue;
        // An unknown holder count does not withhold a token the user holds:
        // only a count the explorer actually reported as below the threshold
@@ -230,6 +232,7 @@ function updateSendBalance() {
            token,
            addr.tokenBalances,
            state.trackedTokens,
+            currentNetwork().chainId,
        );
        // A null balance is a holding whose scale is unknown. Saying a figure
        // for it would be a claim about the amount, so it reads as the
@@ -385,6 +388,7 @@ function init(_ctx) {
                token,
                addr.tokenBalances,
                state.trackedTokens,
+                currentNetwork().chainId,
            );
            ({ tokenDecimals } = tokenBalanceAndDecimals(addr, token));
        }
@@ -29,7 +29,7 @@
 // string, and a token the user added by hand carries whatever lookupTokenInfo()
 // got back, so the accepted types are enumerated rather than coerced.
 const { toDecimals } = require("./transferAmount");
-const { TOKEN_BY_ADDRESS } = require("./tokenList");
+const { bundledToken } = require("./tokenList");
 const { isSpoofedSymbol } = require("./symbolSpoof");

 // Every decimals the explorer reported for this contract, across all the
@@ -53,12 +53,14 @@ function explorerDecimals(lower, wallets) {
 }

 // The decimals to render a token amount with, or null when nothing knows.
-// `sources` is { trackedTokens, wallets }, both shaped as they are on `state`.
+// `sources` is { chainId, trackedTokens, wallets }. `chainId` is the chain id
+// of the token's network. The bundled list is read only when that network is
+// Ethereum Mainnet. `trackedTokens` and `wallets` are shaped as on `state`.
 function resolveTokenDecimals(tokenAddress, sources) {
    const lower = (tokenAddress || "").toLowerCase();
    if (!lower) return null;

-    const bundled = TOKEN_BY_ADDRESS.get(lower);
+    const bundled = bundledToken(lower, sources && sources.chainId);
    if (bundled) {
        const d = toDecimals(bundled.decimals);
        if (d !== null) return d;
@@ -100,18 +102,19 @@ function explorerSymbol(lower, wallets) {
 // explorer reported: the same sources and the same precedence
 // resolveTokenDecimals() uses, so a token's name and its scale are drawn from
 // the same place and the two can no longer disagree about which sources they
-// trust. `sources` is { trackedTokens, wallets }, shaped as on `state`.
+// trust. `sources` is as for resolveTokenDecimals().
 //
 // A tracked or explorer-reported symbol is attacker-influenced text, so it is
-// held to the spoof rule (symbolSpoof.js): a candidate that wears a bundled or
-// native ticker from a contract not entitled to it is refused and the next
-// source tried, so resolving a symbol never becomes a new way to claim a known
-// ticker. The bundled list is the wallet's own data and is trusted as it is.
+// held to the spoof rule (symbolSpoof.js): a candidate that the rule calls a
+// spoof is refused and the next source tried, so resolving a symbol never
+// becomes a new way to claim a known ticker. The bundled list is the wallet's
+// own data and is trusted as it is.
 function resolveTokenSymbol(tokenAddress, sources) {
    const lower = (tokenAddress || "").toLowerCase();
    if (!lower) return null;

-    const bundled = TOKEN_BY_ADDRESS.get(lower);
+    const chainId = sources && sources.chainId;
+    const bundled = bundledToken(lower, chainId);
    if (bundled && bundled.symbol) return bundled.symbol;

    const tracked = ((sources && sources.trackedTokens) || []).find(
@@ -123,7 +126,7 @@ function resolveTokenSymbol(tokenAddress, sources) {
    if (reported) candidates.push(reported);

    for (const symbol of candidates) {
-        if (!isSpoofedSymbol(symbol, tokenAddress)) return symbol;
+        if (!isSpoofedSymbol(symbol, tokenAddress, chainId)) return symbol;
    }
    return null;
 }
@@ -17,7 +17,7 @@ const { ERC20_ABI } = require("./constants");
 const { NETWORKS } = require("./networks");
 const { log, debugFetch, urlOrigin } = require("./log");
 const { deriveAddressFromXpub } = require("./wallet");
-const { TOKEN_BY_ADDRESS } = require("./tokenList");
+const { bundledToken } = require("./tokenList");
 const { LOW_HOLDER_THRESHOLD, parseHoldersCount } = require("./holders");
 const { isSpoofedSymbol } = require("./symbolSpoof");
 const { toDecimals } = require("./transferAmount");
@@ -106,6 +106,9 @@ function rawUnits(value) {
 // balance is read through the RPC endpoint instead, and its row here gives that
 // entry its holder count and `decimals` (fetchTrackedTokenBalances()).
 //
+// `chainId` is the chain id of the network `blockscoutUrl` serves. The known
+// token list is used only when that network is Ethereum Mainnet.
+//
 // `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
 // upstream of every screen that displays a token amount, so a value invented
@@ -117,6 +120,7 @@ async function fetchTokenBalances(
    address,
    blockscoutUrl,
    trackedTokens,
+    chainId,
    signal,
 ) {
    if (!(await storedSettingIsOn("useBlockscout"))) return [];
@@ -175,7 +179,10 @@ async function fetchTokenBalances(
            // either way: copying another source into it would make
            // explorerDecimals()'s disagreement check compare something other
            // than explorer values.
-            const known = resolveTokenDecimals(tokenAddr, { trackedTokens });
+            const known = resolveTokenDecimals(tokenAddr, {
+                chainId,
+                trackedTokens,
+            });
            const scale = known !== null ? known : decimals;
            // null is a holding of an amount that cannot be stated, which is
            // not the same as a holding of zero, and must never render as one.
@@ -191,7 +198,7 @@ async function fetchTokenBalances(
            // through to the views, where the two low-holder filters treat
            // an unknown count as "do not judge" rather than as zero.
            const holders = parseHoldersCount(item.token.holders_count);
-            const isKnown = TOKEN_BY_ADDRESS.has(tokenAddr);
+            const isKnown = bundledToken(tokenAddr, chainId) !== null;
            const isTracked = trackedSet.has(tokenAddr);
            const hasEnoughHolders = holders >= LOW_HOLDER_THRESHOLD;

@@ -202,7 +209,9 @@ async function fetchTokenBalances(
            // Every row here is an ERC-20 the explorer reported, so it has a
            // contract address; the native ETH balance is fetched over RPC in
            // refreshBalances and never passes through this loop.
-            if (isSpoofedSymbol(item.token.symbol, tokenAddr)) continue;
+            if (isSpoofedSymbol(item.token.symbol, tokenAddr, chainId)) {
+                continue;
+            }

            balances.push({
                address: item.token.address_hash,
@@ -249,17 +258,18 @@ async function fetchTokenBalances(
 // 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().
+// `chainId` and `signal` are as for fetchTokenBalances().
 async function fetchTrackedTokenBalances(
    provider,
    address,
    trackedTokens,
    previous,
    explorerRequest,
+    chainId,
    signal,
 ) {
    const listed = trackedTokens.filter(
-        (token) => !isSpoofedSymbol(token.symbol, token.address),
+        (token) => !isSpoofedSymbol(token.symbol, token.address, chainId),
    );
    // Each token's balanceOf answer, or null where it failed.
    const balances = await Promise.all(
@@ -301,7 +311,7 @@ async function fetchTrackedTokenBalances(
        if (raw === 0n) return;
        const entry = entryIn(reported);
        const decimals = entry ? entry.decimals : null;
-        const known = resolveTokenDecimals(lower, { trackedTokens });
+        const known = resolveTokenDecimals(lower, { chainId, trackedTokens });
        const scale = known !== null ? known : decimals;
        rows.push({
            address: token.address,
@@ -330,6 +340,7 @@ async function refreshBalances(
 ) {
    log.debugf("refreshBalances start, rpc:", urlOrigin(rpcUrl));
    const provider = getProvider(rpcUrl, networkId);
+    const { chainId } = requireNetworkId(networkId);
    const tracked = trackedTokens || [];
    const trackedSet = new Set(tracked.map((t) => t.address.toLowerCase()));
    const updates = [];
@@ -393,6 +404,7 @@ async function refreshBalances(
                addr.address,
                blockscoutUrl,
                tracked,
+                chainId,
                signal,
            );
            updates.push(
@@ -403,6 +415,7 @@ async function refreshBalances(
                        tracked,
                        previous,
                        explorerRequest,
+                        chainId,
                        signal,
                    ),
                    explorerRequest,
@@ -61,31 +61,20 @@ function clearPopupCaches() {
 // (https://git.eeqj.de/sneak/AutistMask/issues/653,
 // https://git.eeqj.de/sneak/AutistMask/issues/692).
 //
-// When the stored record is on another network, a switch saved elsewhere has
-// not reached this page yet. This page first takes that switch with
-// takeStoredNetwork() (state.js), as followStoredSettings() does. The switch to
-// `newNetworkId` is then made from the stored record's network. So every
-// network's list of tracked tokens in the stored record is kept
-// (https://git.eeqj.de/sneak/AutistMask/issues/701). When the stored record is
-// already on `newNetworkId`, the switch made from there only resets the
-// balances and caches.
-//
 // Before the switch, `state` takes the tracked tokens that another page stored
 // since this page's last save (takeStoredTrackedTokens() in state.js). The
 // switch then puts them away under the previous network, the network they were
-// added on.
+// added on. When the stored record is on another network, a switch saved
+// elsewhere has not reached this page yet. The stored record's tokens are then
+// that network's, and none are taken.
 async function onChainSwitch(newNetworkId) {
-    const {
-        state,
-        saveState,
-        takeStoredNetwork,
-        takeStoredTrackedTokens,
-    } = require("./state");
+    const { state, saveState, takeStoredTrackedTokens } = require("./state");
    let net = null;
    await saveState((stored) => {
        if (state.networkId === newNetworkId) return false;
-        if (stored.networkId !== state.networkId) takeStoredNetwork(stored);
-        takeStoredTrackedTokens(stored);
+        if (stored.networkId === state.networkId) {
+            takeStoredTrackedTokens(stored);
+        }
        net = applyChainSwitchFields(state, newNetworkId);
        stored.lastBalanceRefresh = 0;
        stored.fraudContracts = [];
@@ -527,26 +527,6 @@ async function saveStateOnce(beforeWrite) {
            merged[key] = current[key];
        }
    }
-    // When the merged record names a network other than this page's, this page
-    // has not yet taken a switch saved elsewhere. This page's `trackedTokens`
-    // is then the list of this page's network. The stored record keeps the
-    // list of this page's network in `networkTrackedTokens`. So a token that
-    // this page added or removed since its last save is added to or removed
-    // from that stored list. The merged record keeps the stored `trackedTokens`
-    // (https://git.eeqj.de/sneak/AutistMask/issues/701).
-    if (merged.networkId !== current.networkId) {
-        merged.trackedTokens = fresh.trackedTokens;
-        merged.networkTrackedTokens = {
-            ...fresh.networkTrackedTokens,
-            [current.networkId]: mergeListByIdentity(
-                baseline.trackedTokens,
-                current.trackedTokens,
-                fresh.networkTrackedTokens[current.networkId],
-                (token) => token.address.toLowerCase(),
-                (base, ours) => ours,
-            ),
-        };
-    }
    merged.hasWallet = Boolean(merged.wallets && merged.wallets.length > 0);
    // Stamped on every write, never merged or diffed: the record that goes to
    // storage is in THIS build's shape whatever shape it was read in, which is
@@ -628,12 +608,11 @@ function saveState(beforeWrite) {
 }

 // 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 and
-// onChainSwitch() in src/shared/chainSwitch.js call 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.
+// 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));
@@ -19,7 +19,8 @@
 // them hid the other one's holders' money (issue #276).  Membership, not
 // equality, is therefore the question — but it is the same question, asked of
 // a table that can now state the truth.  Every address in a set is one the
-// wallet ships as a real token; a contract outside the set is still a spoof.
+// wallet ships as a real token on Ethereum Mainnet.  On mainnet, a contract
+// outside the set is still a spoof.
 //
 // The symbol is attacker-controlled — it is whatever the ERC-20 contract
 // returns — so the lookup is done on a normalized form (issue #260): the
@@ -27,6 +28,7 @@
 // since that is what the user acts on.

 const { KNOWN_SYMBOLS } = require("./tokenList");
+const { NETWORKS } = require("./networks");

 // Ethereum addresses are case-insensitive: EIP-55 mixed case is a checksum
 // over the address, not part of its identity.
@@ -93,18 +95,24 @@ function normalizeSymbol(symbol) {
 }

 // True when a token bearing `symbol` from contract `contractAddress` is
-// impersonating a known symbol.
+// impersonating a known symbol. `chainId` is the chain id of the token's
+// network.
+//
+// The native asset's labels are known symbols on every network. The bundled
+// list's symbols are known symbols only on Ethereum Mainnet, because the list
+// holds mainnet contracts.
 //
 // An empty contract address is the native asset, which is never a spoof:
 // this is what keeps the user's real ETH out of the rule, and it holds for
 // any symbol that becomes null-mapped later, not just for ETH.
-function isSpoofedSymbol(symbol, contractAddress) {
+function isSpoofedSymbol(symbol, contractAddress, chainId) {
    const contract = normalizeAddress(contractAddress);
    if (!contract) return false;
    const sym = normalizeSymbol(symbol);
    if (!KNOWN_SYMBOLS.has(sym)) return false;
    const legit = KNOWN_SYMBOLS.get(sym);
    if (legit === null) return true;
+    if (chainId !== NETWORKS.mainnet.chainId) return false;
    return !legit.has(contract);
 }

@@ -3953,6 +3953,15 @@ for (const t of TOKENS) {
    TOKEN_BY_ADDRESS.set(t.address.toLowerCase(), t);
 }

+// The bundled list's entry for the contract at `address` on the network with
+// chain id `chainId`, or null. The list holds Ethereum Mainnet contracts only.
+// A contract at the same address on another network is another token, so any
+// other chain id gets null.
+function bundledToken(address, chainId) {
+    if (chainId !== NETWORKS.mainnet.chainId) return null;
+    return TOKEN_BY_ADDRESS.get((address || "").toLowerCase()) || null;
+}
+
 // Build a map of symbol (uppercased) -> the set of contract addresses
 // (lowercased) that legitimately bear it.  Used for spoofed-symbol detection.
 // "ETH" maps to null: the native asset has no contract, so no contract may
@@ -3969,7 +3978,8 @@ for (const t of TOKENS) {
 // hides from the balance list, the history and the send selector at its own
 // address, so the user cannot spend it (issue #276).  Naming every address
 // that bears the symbol is the only shape that says what is true; it does not
-// loosen the rule, because a contract outside the set is still a spoof.
+// loosen the rule.  On Ethereum Mainnet, a contract outside the set is still a
+// spoof.
 const KNOWN_SYMBOLS = new Map();
 KNOWN_SYMBOLS.set("ETH", null);
 for (const network of Object.values(NETWORKS)) {
@@ -3988,14 +3998,15 @@ for (const t of TOKENS) {
    }
 }

-// Resolve a token symbol from multiple sources, never returning "?".
-function resolveSymbol(tokenAddress, tokenBalances, trackedTokens) {
+// Resolve a token symbol from multiple sources, never returning "?". The token
+// is a contract on the network with chain id `chainId`.
+function resolveSymbol(tokenAddress, tokenBalances, trackedTokens, chainId) {
    const lower = (tokenAddress || "").toLowerCase();
    const tb = (tokenBalances || []).find(
        (t) => t.address.toLowerCase() === lower,
    );
    if (tb && tb.symbol) return tb.symbol;
-    const known = TOKEN_BY_ADDRESS.get(lower);
+    const known = bundledToken(lower, chainId);
    if (known && known.symbol) return known.symbol;
    const tracked = (trackedTokens || []).find(
        (t) => t.address.toLowerCase() === lower,
@@ -4012,5 +4023,6 @@ module.exports = {
    USD_PRICE_FEEDS,
    PRICE_FEED_BY_ADDRESS,
    getTopTokens,
+    bundledToken,
    resolveSymbol,
 };
@@ -8,7 +8,7 @@

 const { formatEther, formatUnits } = require("ethers");
 const { log, debugFetch } = require("./log");
-const { TOKEN_BY_ADDRESS } = require("./tokenList");
+const { bundledToken } = require("./tokenList");
 const { parseHoldersCount, isLowHolderCount } = require("./holders");
 const { isSpoofedSymbol } = require("./symbolSpoof");
 const { nativeCurrencyByChainId } = require("./networks");
@@ -47,7 +47,7 @@ function parseTx(tx, addrLower, chainId) {
    let direction = normalizeAddress(from) === addrLower ? "sent" : "received";
    let directionLabel = direction === "sent" ? "Sent" : "Received";
    if (toIsContract && method && method !== "transfer") {
-        const token = TOKEN_BY_ADDRESS.get(normalizeAddress(to));
+        const token = bundledToken(to, chainId);
        if (token) {
            symbol = token.symbol;
        }
@@ -317,7 +317,10 @@ function filterTransactions(txs, filters = {}) {
        const contract = normalizeAddress(tx.contractAddress);

        // Filter spoofed known symbols and record the fraud contract
-        if (hideSpoofed && isSpoofedSymbol(tx.symbol, tx.contractAddress)) {
+        if (
+            hideSpoofed &&
+            isSpoofedSymbol(tx.symbol, tx.contractAddress, tx.chainId)
+        ) {
            if (contract && !fraudSet.has(contract)) {
                fraudSet.add(contract);
                newFraud.push(contract);
@@ -452,8 +452,8 @@ const ADDRESS_THIS = "0x0000000000000000000000000000000000000002";
 // `decimals` is null when nothing knows this token's scale. It is not
 // defaulted to 18: the swap lines land on the same approval screen as the
 // ERC-20 line, and a scale guessed there is what showed a 1,000 USDT swap as
-// 0.000000000001. `sources` is { trackedTokens, wallets }, shaped as they are
-// on `state`; resolveTokenDecimals() reads the bundled list, then those.
+// 0.000000000001. `sources` is as for resolveTokenDecimals(), which reads the
+// bundled list on Ethereum Mainnet, then the tracked tokens and the wallets.
 //
 // A null `address` means UNDETERMINED — the calldata named no currency for
 // that side — and is refused rather than named. It is not native ETH: Uniswap
@@ -1240,6 +1240,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
    const release = routerRelease(toAddress, chainId);
    if (release === null) return null;
    const { commandTypeMask, commands, allowRevert } = release;
+    // The swap's tokens are contracts on the network with `chainId`, so they
+    // are named and scaled for that network.
+    const tokenSources = { ...sources, chainId };
    try {
        const parsed = ROUTER_IFACE.parseTransaction({ data });
        if (!parsed) return null;
@@ -2208,11 +2211,11 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
        // Any other output keeps its own token and figure: a swap that pays
        // its WETH to the user and then unwraps receives WETH, and one that
        // buys USDC and then unwraps the WETH it did not spend receives USDC.
-        const inInfo = tokenInfo(inputToken, sources);
+        const inInfo = tokenInfo(inputToken, tokenSources);
        const outInfo =
            outputUnwrapped || (hasUnwrapWeth && !outputEstablished)
                ? { symbol: "ETH", decimals: 18, address: null }
-                : tokenInfo(outputToken, sources);
+                : tokenInfo(outputToken, tokenSources);

        const inSymbol = inInfo.symbol;
        const outSymbol = outInfo.symbol;
@@ -2337,13 +2340,19 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
            details.push({
                label: "Moved from the sender",
                value: present(s.amount)
-                    ? spentText(s.amount, tokenInfo(s.token, sources), s.atMost)
-                          .display
+                    ? spentText(
+                          s.amount,
+                          tokenInfo(s.token, tokenSources),
+                          s.atMost,
+                      ).display
                    : UNDECODED_CURRENCY,
            });
            if (present(s.token)) {
                details.push(
-                    tokenMovedLine("Token moved", tokenInfo(s.token, sources)),
+                    tokenMovedLine(
+                        "Token moved",
+                        tokenInfo(s.token, tokenSources),
+                    ),
                );
                details.push({
                    label: "Moved to",
@@ -2355,7 +2364,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
        // What each PERMIT2_TRANSFER_FROM moves: its amount, its token and
        // where it goes, an address on a line of its own.
        for (const m of movedFromSender) {
-            const info = permit2TokenInfo(m.token, sources);
+            const info = permit2TokenInfo(m.token, tokenSources);
            details.push({
                label: "Moved from the sender",
                value: amountText(m.amount, info).display,
@@ -2390,7 +2399,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                });
                continue;
            }
-            const info = permit2TokenInfo(p.token, sources);
+            const info = permit2TokenInfo(p.token, tokenSources);
            details.push({
                label: "Permit2 allowance",
                value:
@@ -2456,7 +2465,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
            paidTo.push({ label: "Paid to", value: PAID_TO_BRIDGE });
        }
        for (const m of movedIntoRouter) {
-            const info = permit2TokenInfo(m.token, sources);
+            const info = permit2TokenInfo(m.token, tokenSources);
            paidTo.push({
                label: "Paid to",
                value:
@@ -2481,7 +2490,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
            paidTo.push(
                tokenMovedLine(
                    "Token moved into the router",
-                    tokenInfo(getAddress(token), sources),
+                    tokenInfo(getAddress(token), tokenSources),
                ),
            );
        }
@@ -90,9 +90,11 @@ beforeEach(() => {
 });

 describe("resolveTokenDecimals", () => {
+    // The bundled list is read only for a token on Ethereum Mainnet.
    test("prefers the bundled list", () => {
        state.trackedTokens = [{ address: USDC, symbol: "USDC", decimals: 2 }];
-        expect(resolveTokenDecimals(USDC, state)).toBe(6);
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenDecimals(USDC, sources)).toBe(6);
    });

    test("reads a token the user tracks", () => {
@@ -124,7 +126,8 @@ describe("resolveTokenDecimals", () => {
    // answers 0 is used rather than fallen past like the unusable entry above.
    test("uses a bundled scale of zero", () => {
        state.trackedTokens = [{ address: SLP, symbol: "SLP", decimals: 18 }];
-        expect(resolveTokenDecimals(SLP, state)).toBe(0);
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenDecimals(SLP, sources)).toBe(0);
    });

    test("uses a tracked scale of zero", () => {
@@ -0,0 +1,169 @@
+// The approval screen for a site's Sepolia transfer of the contract at USDC's
+// mainnet address, while Sepolia is active.
+//
+// The bundled token list holds Ethereum Mainnet contracts. The contract at the
+// same address on Sepolia is another token, but the screen named it USDC and
+// scaled its amount at USDC's decimals
+// (https://git.eeqj.de/sneak/AutistMask/issues/632). The bundled list now names
+// a token only on Ethereum Mainnet. The same screen for a mainnet transfer of
+// USDC, while Sepolia is active, still names USDC.
+//
+// Driven through the real approval screen, against the minimal DOM stub
+// tests/approvalTokenNetwork.test.js uses.
+
+globalThis.chrome = {
+    storage: { local: { get: async () => ({}), set: async () => {} } },
+};
+
+const { Interface } = require("ethers");
+const { state } = require("../src/shared/state");
+const { NETWORKS } = require("../src/shared/networks");
+const approval = require("../src/popup/views/approval");
+
+const FROM = "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266";
+const RECIPIENT = "0x711e691962E5c054b78071C789A0C8CE657377aD";
+// USDC's address on Ethereum Mainnet, where the bundled list names it.
+const USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
+
+// FROM sends 1234500000 base units to RECIPIENT.
+const TRANSFER_DATA = new Interface([
+    "function transfer(address to, uint256 amount)",
+]).encodeFunctionData("transfer", [RECIPIENT, 1234500000n]);
+
+function makeElement(id) {
+    const classes = new Set();
+    const el = {
+        id,
+        textContent: "",
+        value: "",
+        innerHTML: "",
+        disabled: false,
+        style: {},
+        dataset: {},
+        listeners: {},
+        classList: {
+            add: (...names) => names.forEach((n) => classes.add(n)),
+            remove: (...names) => names.forEach((n) => classes.delete(n)),
+            contains: (n) => classes.has(n),
+            toggle: (n, force) => {
+                const on = force === undefined ? !classes.has(n) : force;
+                if (on) classes.add(n);
+                else classes.delete(n);
+                return on;
+            },
+        },
+        addEventListener: (name, fn) => {
+            el.listeners[name] = el.listeners[name] || [];
+            el.listeners[name].push(fn);
+        },
+        querySelectorAll: () => [],
+        appendChild: () => {},
+    };
+    // Views reach for .parentElement to hide whole sections.
+    Object.defineProperty(el, "parentElement", {
+        get: () => node(id + "-parent"),
+    });
+    return el;
+}
+
+function makeDocument() {
+    const els = new Map();
+    return {
+        getElementById(id) {
+            // The debug banner is created on demand by helpers.js; absent
+            // is the state a non-debug, non-testnet popup is in.
+            if (id === "debug-banner") return null;
+            if (!els.has(id)) els.set(id, makeElement(id));
+            return els.get(id);
+        },
+        createElement: () => makeElement("created"),
+        body: { prepend: () => {} },
+    };
+}
+
+function node(id) {
+    return globalThis.document.getElementById(id);
+}
+
+// One line of the decoded details: its label and what is drawn under it.
+function decodedLine(label) {
+    return node("approve-tx-decoded-details")
+        .innerHTML.split('<div class="mb-2">')
+        .find((line) =>
+            line.startsWith(`<div class="text-muted">${label}</div>`),
+        );
+}
+
+// Open the approval screen, with Sepolia active, for the site's transaction
+// sending TRANSFER_DATA to the contract at USDC's address on the network with
+// chain id `chainId`.
+async function showTransfer(chainId) {
+    globalThis.document = makeDocument();
+    globalThis.window = { location: { search: "" }, close: () => {} };
+    globalThis.chrome.runtime = {
+        connect: () => ({ postMessage: () => {} }),
+        sendMessage: (msg, reply) => {
+            if (!reply) return;
+            reply({
+                type: "tx",
+                origin: "https://dapp.example",
+                isPhishingDomain: false,
+                approvedFrom: FROM,
+                approvedTx: {
+                    type: 2,
+                    from: FROM,
+                    chainId,
+                    nonce: "0x7",
+                    gasLimit: "0x30d40",
+                    maxPriorityFeePerGas: "0x3b9aca00",
+                    maxFeePerGas: "0x77359400",
+                    to: USDC,
+                    value: "0x0",
+                    data: TRANSFER_DATA,
+                    accessList: [],
+                },
+            });
+        },
+    };
+    state.networkId = "sepolia";
+    state.trackedTokens = [];
+    state.networkTrackedTokens = {};
+    state.activeAddress = FROM;
+    state.wallets = [
+        {
+            type: "hd",
+            name: "Wallet 1",
+            xpub: "xpub-wallet-1",
+            encryptedSecret: "encrypted-secret-1",
+            nextIndex: 1,
+            addresses: [
+                { address: FROM, index: 0, balance: "0", tokenBalances: [] },
+            ],
+        },
+    ];
+    state.currentView = null;
+    approval.init({});
+    await approval.show(1);
+}
+
+test("names no token, and states the amount in base units", async () => {
+    await showTransfer(NETWORKS.sepolia.chainId);
+    expect(state.currentView).toBe("approve-tx");
+    expect(node("approve-tx-to").innerHTML).not.toContain("USDC");
+    expect(decodedLine("Token")).toContain(
+        '<div class="font-bold">Unknown token</div>',
+    );
+    expect(decodedLine("Amount")).toContain(
+        '<div class="font-bold">1234500000 base units (decimals unknown)</div>',
+    );
+});
+
+// A transaction is named for its own network, not the active one.
+test("a mainnet transfer of USDC is still named and scaled as USDC", async () => {
+    await showTransfer(NETWORKS.mainnet.chainId);
+    expect(state.currentView).toBe("approve-tx");
+    expect(decodedLine("Token")).toContain('<div class="font-bold">USDC</div>');
+    expect(decodedLine("Amount")).toContain(
+        '<div class="font-bold">1234.5000 USDC</div>',
+    );
+});
@@ -0,0 +1,81 @@
+// The token screen, the Send screen and the confirmation screen for the
+// contract at USDC's mainnet address. No address holds it and the user does
+// not track it, so only the bundled token list can name it.
+//
+// The bundled token list holds Ethereum Mainnet contracts, so these screens
+// name the token from it on Ethereum Mainnet only
+// (https://git.eeqj.de/sneak/AutistMask/issues/632). Driven through the real
+// popup over a stored profile.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+} = require("./support/popupBoot");
+
+const USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
+const RECIPIENT = "0x711e691962E5c054b78071C789A0C8CE657377aD";
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// The popup reopened onto AddressToken for USDC's address, on `networkId`.
+function bootOnToken(networkId) {
+    return bootPopup(
+        unversionedValidProfile({
+            networkId,
+            currentView: "address-token",
+            viewStack: ["main", "address"],
+            selectedWallet: 0,
+            selectedAddress: 0,
+            selectedToken: USDC,
+        }),
+    );
+}
+
+// AddressToken's Send, then Review for 1 token to RECIPIENT.
+async function reviewSend(boot) {
+    await boot.click("btn-address-token-send");
+    expect(boot.visibleViews()).toEqual(["send"]);
+    boot.node("send-to").value = RECIPIENT;
+    boot.node("send-amount").value = "1";
+    await boot.click("btn-send-review");
+    expect(boot.visibleViews()).toEqual(["confirm-tx"]);
+}
+
+describe("on Ethereum Mainnet, the bundled list names the token", () => {
+    test("on the token screen", async () => {
+        const boot = await bootOnToken("mainnet");
+        expect(boot.visibleViews()).toEqual(["address-token"]);
+        expect(boot.text("address-token-title")).toContain("USDC");
+        const info = boot.node("address-token-contract-info").innerHTML;
+        expect(info).toContain(
+            '<span class="text-muted">Decimals:</span> 6</div>',
+        );
+    });
+
+    test("on the Send screen and the confirmation screen", async () => {
+        const boot = await bootOnToken("mainnet");
+        await reviewSend(boot);
+        expect(boot.text("send-balance")).toContain("USDC");
+        expect(boot.text("confirm-amount")).toContain("USDC");
+    });
+});
+
+describe("with Sepolia active, the bundled list does not name the token", () => {
+    test("on the token screen", async () => {
+        const boot = await bootOnToken("sepolia");
+        expect(boot.visibleViews()).toEqual(["address-token"]);
+        expect(boot.text("address-token-title")).not.toContain("USDC");
+        const info = boot.node("address-token-contract-info").innerHTML;
+        expect(info).not.toContain("Decimals:");
+    });
+
+    test("on the Send screen and the confirmation screen", async () => {
+        const boot = await bootOnToken("sepolia");
+        await reviewSend(boot);
+        expect(boot.text("send-balance")).not.toContain("USDC");
+        expect(boot.text("confirm-amount")).not.toContain("USDC");
+    });
+});
@@ -111,13 +111,15 @@ function respondWith(items) {
 }

 // Fetch and place the result exactly where refreshBalances() places it, so the
-// approval screens read what a real refresh would have left on state.
+// approval screens read what a real refresh on Ethereum Mainnet would have
+// left on state.
 async function fetchOnto(items, trackedTokens = []) {
    respondWith(items);
    const balances = await fetchTokenBalances(
        HOLDER,
        BLOCKSCOUT,
        trackedTokens,
+        "0x1",
    );
    state.trackedTokens = trackedTokens;
    state.wallets = [
@@ -192,7 +192,13 @@ describe("the balance-list spam gate", () => {
                },
            }),
        ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+        // On Ethereum Mainnet, the only network the known-token list covers.
+        const balances = await fetchTokenBalances(
+            HOLDER,
+            BLOCKSCOUT,
+            [],
+            "0x1",
+        );
        expect(balances).toHaveLength(1);
        expect(balances[0].holders).toBeNull();
    });
@@ -67,13 +67,15 @@ beforeEach(() => {
 });

 describe("resolveTokenSymbol", () => {
+    // The bundled list is read only for a token on Ethereum Mainnet.
    test("reads the bundled list", () => {
-        expect(resolveTokenSymbol(USDC, state)).toBe("USDC");
+        expect(resolveTokenSymbol(USDC, { chainId: "0x1" })).toBe("USDC");
    });

    test("prefers the bundled list over a tracked entry", () => {
        state.trackedTokens = [{ address: USDC, symbol: "NOTUSDC" }];
-        expect(resolveTokenSymbol(USDC, state)).toBe("USDC");
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenSymbol(USDC, sources)).toBe("USDC");
    });

    test("reads a token the user tracks", () => {
@@ -104,7 +106,19 @@ describe("resolveTokenSymbol", () => {
    test("rejects a tracked entry claiming a bundled ticker it is not", () => {
        // NOVEL_TOKEN is not the real USDC contract, so it may not wear USDC.
        state.trackedTokens = [{ address: NOVEL_TOKEN, symbol: "USDC" }];
-        expect(resolveTokenSymbol(NOVEL_TOKEN, state)).toBeNull();
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenSymbol(NOVEL_TOKEN, sources)).toBeNull();
+    });
+
+    // The bundled list holds mainnet contracts, so on Sepolia any contract may
+    // carry one of its symbols.
+    test("on Sepolia, reads a tracked entry carrying a bundled ticker", () => {
+        state.trackedTokens = [{ address: NOVEL_TOKEN, symbol: "USDC" }];
+        const sources = {
+            chainId: "0xaa36a7",
+            trackedTokens: state.trackedTokens,
+        };
+        expect(resolveTokenSymbol(NOVEL_TOKEN, sources)).toBe("USDC");
    });

    test("rejects an explorer entry claiming the native ETH ticker", () => {
@@ -72,6 +72,11 @@ const {
 const { renderSendTokenSelect } = require("../src/popup/views/send");
 const { state } = require("../src/shared/state");
 const { debugFetch } = require("../src/shared/log");
+const { NETWORKS } = require("../src/shared/networks");
+
+// The bundled list's symbols are known symbols only on Ethereum Mainnet.
+const MAINNET = NETWORKS.mainnet.chainId;
+const SEPOLIA = NETWORKS.sepolia.chainId;

 // The fake "Ethereum" token with symbol "ETH" from the attack documented in
 // README.md, given a holder count high enough to clear every other filter so
@@ -116,14 +121,29 @@ describe("the shared rule", () => {
    });

    test("a known symbol from its own contract is not a spoof", () => {
-        expect(isSpoofedSymbol("USDC", USDC_CONTRACT)).toBe(false);
-        expect(isSpoofedSymbol("usdc", USDC_CONTRACT.toUpperCase())).toBe(
-            false,
-        );
+        expect(isSpoofedSymbol("USDC", USDC_CONTRACT, MAINNET)).toBe(false);
+        expect(
+            isSpoofedSymbol("usdc", USDC_CONTRACT.toUpperCase(), MAINNET),
+        ).toBe(false);
    });

    test("a known symbol from another contract is a spoof", () => {
-        expect(isSpoofedSymbol("USDC", FAKE_ETH_CONTRACT)).toBe(true);
+        expect(isSpoofedSymbol("USDC", FAKE_ETH_CONTRACT, MAINNET)).toBe(true);
+    });
+
+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+    // mainnet contracts, so on Sepolia any contract may carry one of its
+    // symbols.
+    test("on Sepolia, a bundled symbol from any contract is not a spoof", () => {
+        expect(isSpoofedSymbol("USDC", FAKE_ETH_CONTRACT, SEPOLIA)).toBe(false);
+        expect(isSpoofedSymbol("USDC", USDC_CONTRACT, SEPOLIA)).toBe(false);
+    });
+
+    test("on Sepolia, the native asset's labels are still reserved", () => {
+        expect(isSpoofedSymbol("ETH", FAKE_ETH_CONTRACT, SEPOLIA)).toBe(true);
+        expect(isSpoofedSymbol("SepoliaETH", FAKE_ETH_CONTRACT, SEPOLIA)).toBe(
+            true,
+        );
    });

    test("a symbol that is not in the table is not judged here", () => {
@@ -164,7 +184,9 @@ describe("the shared rule: symbols that render as a known symbol", () => {
    test("ASCII padding does not buy a pass", () => {
        expect(isSpoofedSymbol(" ETH ", FAKE_ETH_CONTRACT)).toBe(true);
        expect(isSpoofedSymbol("\tETH\n", FAKE_ETH_CONTRACT)).toBe(true);
-        expect(isSpoofedSymbol("  usdc  ", FAKE_ETH_CONTRACT)).toBe(true);
+        expect(isSpoofedSymbol("  usdc  ", FAKE_ETH_CONTRACT, MAINNET)).toBe(
+            true,
+        );
    });

    test("non-breaking and other Unicode spaces do not either", () => {
@@ -243,7 +265,9 @@ describe("the shared rule: symbols that render as a known symbol", () => {

    test("compatibility forms fold onto the symbol they imitate", () => {
        expect(isSpoofedSymbol(FULLWIDTH_ETH, FAKE_ETH_CONTRACT)).toBe(true);
-        expect(isSpoofedSymbol(FULLWIDTH_USDC, FAKE_ETH_CONTRACT)).toBe(true);
+        expect(
+            isSpoofedSymbol(FULLWIDTH_USDC, FAKE_ETH_CONTRACT, MAINNET),
+        ).toBe(true);
    });

    // The two knowingly open classes, asserted here so that the boundary is
@@ -271,8 +295,10 @@ describe("the shared rule: symbols that render as a known symbol", () => {
    });

    test("a genuine contract still bears its own padded symbol", () => {
-        expect(isSpoofedSymbol(" USDC ", USDC_CONTRACT)).toBe(false);
-        expect(isSpoofedSymbol(ZWSP + "WETH", WETH_CONTRACT)).toBe(false);
+        expect(isSpoofedSymbol(" USDC ", USDC_CONTRACT, MAINNET)).toBe(false);
+        expect(isSpoofedSymbol(ZWSP + "WETH", WETH_CONTRACT, MAINNET)).toBe(
+            false,
+        );
    });

    // Normalization must not invent a match.  Interior ASCII whitespace is
@@ -296,7 +322,7 @@ describe("the shared rule: symbols that render as a known symbol", () => {
            expect(symbol).toMatch(/^[!-~]+$/);
            if (addresses === null) continue;
            for (const address of addresses) {
-                expect(isSpoofedSymbol(symbol, address)).toBe(false);
+                expect(isSpoofedSymbol(symbol, address, MAINNET)).toBe(false);
            }
        }
    });
@@ -317,7 +343,7 @@ describe("the shared rule: symbols that render as a known symbol", () => {
 describe("the shipped token list", () => {
    test("no bundled token is filtered at its own address", () => {
        const filtered = TOKENS.filter((t) =>
-            isSpoofedSymbol(t.symbol, t.address),
+            isSpoofedSymbol(t.symbol, t.address, MAINNET),
        ).map((t) => t.symbol + " @ " + t.address);
        expect(filtered).toEqual([]);
    });
@@ -360,7 +386,9 @@ describe("the shipped token list", () => {
        expect(shared.length).toBeGreaterThan(0);
        for (const [, list] of shared) {
            for (const t of list) {
-                expect(isSpoofedSymbol(t.symbol, t.address)).toBe(false);
+                expect(isSpoofedSymbol(t.symbol, t.address, MAINNET)).toBe(
+                    false,
+                );
            }
        }
    });
@@ -404,7 +432,7 @@ describe("the shipped token list", () => {
                [...addresses].sort(),
            );
            for (const address of addresses) {
-                expect(isSpoofedSymbol(symbol, address)).toBe(false);
+                expect(isSpoofedSymbol(symbol, address, MAINNET)).toBe(false);
            }
        }
    });
@@ -421,7 +449,9 @@ describe("the shipped token list", () => {
        }
        for (const [symbol, list] of bySymbol) {
            if (list.length < 2) continue;
-            expect(isSpoofedSymbol(symbol, FAKE_ETH_CONTRACT)).toBe(true);
+            expect(isSpoofedSymbol(symbol, FAKE_ETH_CONTRACT, MAINNET)).toBe(
+                true,
+            );
        }
    });
 });
@@ -506,10 +536,40 @@ describe("surface 2: the Send token selector", () => {
    }

    beforeEach(() => {
+        state.networkId = "mainnet";
        state.fraudContracts = [];
        state.hideLowHolderTokens = true;
    });

+    afterAll(() => {
+        state.networkId = "mainnet";
+    });
+
+    // A token reporting USDC's symbol from another contract.
+    function otherUsdc() {
+        return {
+            address: FAKE_ETH_CONTRACT,
+            symbol: "USDC",
+            decimals: 6,
+            balance: "12.5",
+            holders: 900000,
+        };
+    }
+
+    test("a bundled symbol from another contract is not selectable", () => {
+        render([otherUsdc()]);
+        expect(select.children).toEqual([]);
+    });
+
+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+    // mainnet contracts, so on Sepolia any contract may carry its symbols.
+    test("with Sepolia active, a bundled symbol from another contract is selectable", () => {
+        state.networkId = "sepolia";
+        render([otherUsdc()]);
+        expect(select.children).toHaveLength(1);
+        expect(select.children[0].value).toBe(FAKE_ETH_CONTRACT);
+    });
+
    test("a fake ETH token is not selectable", () => {
        render([
            {
@@ -627,7 +687,12 @@ describe("surface 3: the balance list", () => {
                decimals: "6",
            }),
        ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+        const balances = await fetchTokenBalances(
+            HOLDER,
+            BLOCKSCOUT,
+            [],
+            MAINNET,
+        );
        expect(balances).toHaveLength(1);
        expect(balances[0].symbol).toBe(" USDC ");
    });
@@ -641,11 +706,40 @@ describe("surface 3: the balance list", () => {
                decimals: "6",
            }),
        ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+        const balances = await fetchTokenBalances(
+            HOLDER,
+            BLOCKSCOUT,
+            [],
+            MAINNET,
+        );
        expect(balances).toHaveLength(1);
        expect(balances[0].symbol).toBe("USDC");
    });

+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+    // mainnet contracts, so on Sepolia any contract may carry its symbols.
+    test("a bundled symbol from another contract is listed on Sepolia only", async () => {
+        respondWith([fakeEthItem({ symbol: "USDC", decimals: "6" })]);
+        expect(
+            await fetchTokenBalances(HOLDER, BLOCKSCOUT, [], MAINNET),
+        ).toEqual([]);
+        const sepolia = await fetchTokenBalances(
+            HOLDER,
+            BLOCKSCOUT,
+            [],
+            SEPOLIA,
+        );
+        expect(sepolia).toHaveLength(1);
+        expect(sepolia[0].symbol).toBe("USDC");
+    });
+
+    test("a fake ETH token is filtered on Sepolia too", async () => {
+        respondWith([fakeEthItem()]);
+        expect(
+            await fetchTokenBalances(HOLDER, BLOCKSCOUT, [], SEPOLIA),
+        ).toEqual([]);
+    });
+
    // The trap in this change: the user's real ETH balance is not an ERC-20
    // and is fetched over RPC in refreshBalances, so it never passes through
    // this loop at all.  An explorer row that is not an ERC-20 is dropped
@@ -133,13 +133,13 @@ function trackedRow(balance, decimals = null, holders = null) {
    };
 }

-async function refresh(addresses, trackedTokens) {
+async function refresh(addresses, trackedTokens, networkId = "mainnet") {
    await refreshBalances(
        [{ addresses }],
        RPC_URL,
        EXPLORER_URL,
        trackedTokens,
-        "mainnet",
+        networkId,
        new AbortController().signal,
    );
    return addresses;
@@ -307,3 +307,76 @@ test("a tracked token wearing a known symbol from another contract is not listed
    );
    expect(first.tokenBalances).toEqual([]);
 });
+
+// https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+// Ethereum Mainnet contracts. A token outside the tracked tokens with an
+// unknown holder count is listed only when the bundled list names it.
+test("an untracked bundled token with an unknown holder count is listed on Ethereum Mainnet only", async () => {
+    explorerRows = [explorerRow(USDC, "USDC", 5000000, null)];
+    const [mainnet] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [],
+    );
+    expect(mainnet.tokenBalances).toEqual([
+        {
+            address: USDC,
+            name: "USDC",
+            symbol: "USDC",
+            decimals: 6,
+            balance: "5.0",
+            holders: null,
+        },
+    ]);
+    const [sepolia] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [],
+        "sepolia",
+    );
+    expect(sepolia.tokenBalances).toEqual([]);
+});
+
+test("a tracked token at a bundled token's address takes the bundled scale on Ethereum Mainnet only", async () => {
+    holdings[USDC] = { [FIRST]: 5000000n };
+    // The tracked entry records no decimals, and Blockscout fails.
+    const tracked = [
+        { address: USDC, symbol: "USDC", name: "USD Coin", decimals: null },
+    ];
+    const row = (balance) => ({
+        address: USDC,
+        name: "USD Coin",
+        symbol: "USDC",
+        decimals: null,
+        balance: balance,
+        holders: null,
+    });
+    const [mainnet] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        tracked,
+    );
+    expect(mainnet.tokenBalances).toEqual([row("5.0")]);
+    const [sepolia] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        tracked,
+        "sepolia",
+    );
+    expect(sepolia.tokenBalances).toEqual([row(null)]);
+});
+
+test("with Sepolia active, a tracked token wearing a bundled symbol from another contract is listed", async () => {
+    holdings[OTHER] = { [FIRST]: 5000000n };
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [{ address: OTHER, symbol: "USDC", name: "Other", decimals: 6 }],
+        "sepolia",
+    );
+    expect(first.tokenBalances).toEqual([
+        {
+            address: OTHER,
+            name: "Other",
+            symbol: "USDC",
+            decimals: null,
+            balance: "5.0",
+            holders: null,
+        },
+    ]);
+});
@@ -257,7 +257,6 @@ test("a token tracked on Sepolia when another page switched there is not tracked
        ...boot.storage.read("autistmask"),
        networkId: "sepolia",
        trackedTokens: [SEPOLIA_TOKEN],
-        networkTrackedTokens: { mainnet: [] },
    });

    await chooseNetwork(boot, "sepolia");
@@ -268,103 +267,6 @@ test("a token tracked on Sepolia when another page switched there is not tracked
    expect(stored.networkTrackedTokens.mainnet).toEqual([]);
 });

-// Another popup page saves a switch to Sepolia, where TST is tracked. Before
-// taking that switch, this page adds a token on Ethereum Mainnet. The add's
-// save adds the token to Ethereum Mainnet's list and leaves Sepolia's list as
-// it was.
-test("a token added before this page takes another page's switch is tracked on Ethereum Mainnet", async () => {
-    const boot = await bootOnAddToken("mainnet", {
-        trackedTokens: [MAINNET_TOKEN],
-        networkTrackedTokens: { sepolia: [SEPOLIA_TOKEN] },
-    });
-    expect(boot.pageErrors).toEqual([]);
-    boot.storage.write("autistmask", {
-        ...boot.storage.read("autistmask"),
-        networkId: "sepolia",
-        trackedTokens: [SEPOLIA_TOKEN],
-        networkTrackedTokens: {
-            mainnet: [MAINNET_TOKEN],
-            sepolia: [SEPOLIA_TOKEN],
-        },
-    });
-    const { lookupTokenInfo } = require("../src/shared/balances");
-    lookupTokenInfo.mockResolvedValueOnce({
-        symbol: "NEW",
-        decimals: 18,
-        name: "New Token",
-    });
-
-    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
-    await boot.click("btn-settings-addtoken-manual");
-
-    const stored = boot.storage.read("autistmask");
-    expect(stored.networkId).toBe("sepolia");
-    expect(stored.trackedTokens).toEqual([SEPOLIA_TOKEN]);
-    expect(stored.networkTrackedTokens.mainnet).toEqual([
-        MAINNET_TOKEN,
-        {
-            address: NEW_TOKEN_ADDRESS,
-            symbol: "NEW",
-            decimals: 18,
-            name: "New Token",
-        },
-    ]);
-});
-
-// Another popup page saves a switch to Sepolia, where TST is tracked. Before
-// taking that switch, this page removes DAI on Ethereum Mainnet, as the `[x]`
-// on a tracked token in Settings does. The removal's save drops DAI from
-// Ethereum Mainnet's list and leaves Sepolia's list as it was.
-test("a token removed before this page takes another page's switch is gone from Ethereum Mainnet", async () => {
-    const boot = await bootPopup(
-        unversionedValidProfile({
-            trackedTokens: [MAINNET_TOKEN],
-            networkTrackedTokens: { sepolia: [SEPOLIA_TOKEN] },
-        }),
-    );
-    expect(boot.pageErrors).toEqual([]);
-    boot.storage.write("autistmask", {
-        ...boot.storage.read("autistmask"),
-        networkId: "sepolia",
-        trackedTokens: [SEPOLIA_TOKEN],
-        networkTrackedTokens: {
-            mainnet: [MAINNET_TOKEN],
-            sepolia: [SEPOLIA_TOKEN],
-        },
-    });
-
-    const { state, saveState } = require("../src/shared/state");
-    state.trackedTokens.splice(0, 1);
-    await saveState();
-
-    const stored = boot.storage.read("autistmask");
-    expect(stored.networkId).toBe("sepolia");
-    expect(stored.trackedTokens).toEqual([SEPOLIA_TOKEN]);
-    expect(stored.networkTrackedTokens.mainnet).toEqual([]);
-});
-
-// Another popup page tracks DAI on Ethereum Mainnet and then saves a switch to
-// Sepolia. That switch puts DAI away under Ethereum Mainnet. This page has not
-// taken the switch yet. A switch to Sepolia in this page's Settings keeps DAI
-// on Ethereum Mainnet's list.
-test("a token another page tracked before its own switch stays tracked on Ethereum Mainnet", async () => {
-    const boot = await bootPopup(unversionedValidProfile());
-    expect(boot.pageErrors).toEqual([]);
-    await boot.click("btn-settings");
-    boot.storage.write("autistmask", {
-        ...boot.storage.read("autistmask"),
-        networkId: "sepolia",
-        trackedTokens: [],
-        networkTrackedTokens: { mainnet: [MAINNET_TOKEN] },
-    });
-
-    await chooseNetwork(boot, "sepolia");
-
-    const stored = boot.storage.read("autistmask");
-    expect(stored.networkId).toBe("sepolia");
-    expect(stored.networkTrackedTokens.mainnet).toEqual([MAINNET_TOKEN]);
-});
-
 // Another popup page records a fraud contract on Ethereum Mainnet after this
 // page's last save. The switch to Sepolia drops that fraud contract, as the
 // switch drops this page's own.
@@ -144,6 +144,7 @@ function tokenTx(overrides = {}) {
        isError: false,
        contractAddress: USDC_CONTRACT,
        holders: 3500000,
+        chainId: "0x1",
        ...overrides,
    };
 }
@@ -259,6 +260,32 @@ describe("known-symbol spoof verification", () => {
        expect(result.newFraudContracts).toEqual([NOVEL_SPAM_CONTRACT]);
    });

+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+    // mainnet contracts, so its symbols are not known symbols on Sepolia.
+    test("on Sepolia, a bundled symbol from another contract is kept", () => {
+        const sepoliaToken = tokenTx({
+            symbol: "USDC",
+            contractAddress: NOVEL_SPAM_CONTRACT,
+            holders: 5000000,
+            chainId: "0xaa36a7",
+        });
+        const result = filterTransactions([sepoliaToken], filters());
+        expect(result.transactions).toEqual([sepoliaToken]);
+        expect(result.newFraudContracts).toEqual([]);
+    });
+
+    test('on Sepolia, "ETH" as an ERC-20 is still spoofed', () => {
+        const fakeEth = tokenTx({
+            symbol: "ETH",
+            contractAddress: NOVEL_SPAM_CONTRACT,
+            holders: 5000000,
+            chainId: "0xaa36a7",
+        });
+        expect(filterTransactions([fakeEth], filters()).transactions).toEqual(
+            [],
+        );
+    });
+
    test("the genuine contract for that symbol is not spoofed", () => {
        const genuine = tokenTx();
        const result = filterTransactions([genuine], filters());
@@ -1495,6 +1522,41 @@ describe("fetchRecentTransactions merge and dedup", () => {
        expect(mainnet[0].chainId).toBe("0x1");
    });

+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled token list
+    // names a contract only on Ethereum Mainnet. On Sepolia, a call to the
+    // contract at USDC's mainnet address is labelled with the network's native
+    // currency. A call to any contract the wallet does not name gets that label.
+    test("a contract call on Sepolia is not named by the bundled list", async () => {
+        respondWith(
+            [
+                {
+                    hash: "0x" + "b".repeat(64),
+                    block_number: 21000095,
+                    timestamp: TS,
+                    from: { hash: VICTIM },
+                    to: { hash: USDC_CONTRACT, is_contract: true },
+                    value: "0",
+                    method: "approve",
+                    status: "ok",
+                },
+            ],
+            [],
+        );
+        const sepolia = await fetchRecentTransactions(
+            VICTIM,
+            BLOCKSCOUT,
+            "0xaa36a7",
+        );
+        expect(sepolia[0].directionLabel).toBe("Approve");
+        expect(sepolia[0].symbol).toBe("SepoliaETH");
+        const mainnet = await fetchRecentTransactions(
+            VICTIM,
+            BLOCKSCOUT,
+            "0x1",
+        );
+        expect(mainnet[0].symbol).toBe("USDC");
+    });
+
    test("the fake token transfer survives fetching and is then filtered", async () => {
        respondWith(
            [],
@@ -167,7 +167,8 @@ function row(token = {}, value = FIVE_WETH) {
 }

 // Fetch the explorer's rows through the real fetcher and put them exactly where
-// refreshBalances() puts them. The node reports the holding the explorer does.
+// refreshBalances() puts them on Ethereum Mainnet. The node reports the holding
+// the explorer does.
 async function fetchOnto(items) {
    mockProvider.tokenUnits = BigInt(items[0].value);
    debugFetch.mockImplementation(async () => ({
@@ -176,7 +177,7 @@ async function fetchOnto(items) {
        statusText: "OK",
        json: async () => items,
    }));
-    const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+    const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, [], "0x1");
    state.wallets = [
        {
            name: "Wallet 1",