feat: vendor and censor the phishing blocklist at build time (closes #219)

The blocklist URL in shipped code named a competitor and pointed at a moving
ref, and the extension re-fetched from it every 24 hours, which also meant a
third party decided what this wallet warns about. All of that is gone.

script/vendor-blocklist fetches upstream at a pinned commit, verifies the
sha256 of the bytes that commit serves, and writes
src/shared/phishingBlocklist.json. It is build-time tooling, never shipped, and
the one place in the repo that names the upstream project; a source reference
nobody can verify is not a source reference.

The artifact stores truncated sha256 digests rather than domain names. That is
what censors it: the previous file contained the competitor's name 6,475 times,
as phishing domains impersonating them, and not one of those domains is
dropped. It also makes lookups a binary search over a fixed-width string, so
nothing is built at module load — which matters on MV3, where the worker
re-evaluates the module on every wake — and takes the file from 8.7 MB to
1.7 MB.

script/check-censored enforces the rest: it reads the name out of the vendoring
script rather than repeating it, and fails on any occurrence in the working
tree or under dist/ that is not one of the two literals shipped code cannot
avoid. It runs in make check, which inspects dist/ when there is one and says
loudly when there is not, and again with --require-dist at the end of every
make build.

Removing the runtime fetch retires the delta, the extension-storage persistence
and the 24-hour alarm from #158. A retired alarm is now cleared rather than
left waking the worker forever on installs that already have it.

The e2e suite drives the warning end to end from a real blocklisted origin
served as a real http(s) site, with a control asserting the banner stays hidden
for one that is not listed. Its service-worker interception canary needed a new
anchor, since the startup fetch it used to watch for no longer happens: it now
wakes the worker with a message and asks it for one throwaway fetch.

LICENSE no longer cites a repository that returns 404.

eslint.config.js gains one block: script/lib/ holds node programs the shell
entrypoints call, and without it they lint with no globals at all.

src/background/index.js

@@ -27,14 +27,9 @@ const {
     TX_STAGE_NONCE,
 } = require("../shared/approvalVerify");
 const { prepareApprovalTx } = require("../shared/approvalTx");
-const {
-    isPhishingDomain,
-    refreshPhishingListOnSchedule,
-    initPhishingList,
-} = require("../shared/phishingDomains");
+const { isPhishingDomain } = require("../shared/phishingDomains");
 const {
     BALANCE_REFRESH_ALARM,
-    PHISHING_REFRESH_ALARM,
     BALANCE_REFRESH_PERIOD_MINUTES,
     ensureRecurringAlarms,
     registerAlarmHandlers,
@@ -1003,26 +998,20 @@ async function backgroundRefresh() {
     await saveState();
 }
 
-// Both recurring jobs run off alarms, not timers. On Chrome MV3 this file is
+// The recurring job runs off an alarm, not a timer. On Chrome MV3 this file is
 // a service worker that the browser terminates after about 30 seconds idle,
 // so a setInterval would only ever survive until the first idle period and
 // module-level state does not outlive it. Alarms are held by the browser and
 // wake the worker to deliver them.
 registerAlarmHandlers({
     [BALANCE_REFRESH_ALARM]: backgroundRefresh,
-    // The scheduled refresh, which restores persisted state on a freshly
-    // revived worker and then fetches unconditionally. The freshness guards
-    // belong to the startup path; applying them here would make the tick skip
-    // itself.
-    [PHISHING_REFRESH_ALARM]: refreshPhishingListOnSchedule,
 });
 
 // Everything the background context needs re-established on start. This runs
 // on a fresh install, on browser startup, and on every revival of a
 // terminated worker, so it must be idempotent: ensureRecurringAlarms() only
-// creates alarms that are missing or carrying a stale period, and
-// initPhishingList() fetches only when the persisted timestamps say the list
-// is stale.
+// creates alarms that are missing or carrying a stale period, and only clears
+// retired ones that are still registered.
 //
 // On a fresh install the top-level call and the onInstalled listener both run,
 // close enough together that both could see an alarm missing and create it.
@@ -1033,10 +1022,7 @@ let backgroundJobsRun = null;
 
 function startBackgroundJobs() {
     if (backgroundJobsRun) return backgroundJobsRun;
-    backgroundJobsRun = Promise.all([
-        ensureRecurringAlarms(),
-        initPhishingList(),
-    ])
+    backgroundJobsRun = ensureRecurringAlarms()
         .catch((err) => {
             // An alarm that failed to schedule means a recurring job silently
             // never runs again; it must not be an unhandled rejection.

src/content/inpage.js

@@ -179,7 +179,8 @@
             return this;
         },
 
-        // Some dApps (wagmi) check this to confirm MetaMask-like behavior
+        // Some dApps (wagmi) probe this object to decide whether the provider
+        // supports the de-facto standard extras. The name is theirs, not ours.
         _metamask: {
             isUnlocked() {
                 return Promise.resolve(provider.selectedAddress !== null);

src/shared/alarms.js

@@ -17,16 +17,26 @@
 // run finished and the alarm fires one run-duration earlier than that. Every
 // guard must therefore either be strictly shorter than the period it gates or
 // be bypassed on the scheduled tick — see backgroundRefresh() in
-// src/background/index.js and updatePhishingList() in shared/phishingDomains.js.
+// src/background/index.js.
 
 const { alarmsApi } = require("./browserApi");
 
 const BALANCE_REFRESH_ALARM = "autistmask-balance-refresh";
-const PHISHING_REFRESH_ALARM = "autistmask-phishing-refresh";
+
+// Alarms this extension used to create and no longer has a handler for. A
+// browser keeps an alarm until something clears it, so a job that is deleted
+// from the code goes on waking the service worker on its old schedule forever,
+// on every install that ever ran the version which created it. Removing the job
+// means removing the alarm, so retired names are listed here and cleared on
+// every start until the installs that carry them are long gone.
+const OBSOLETE_ALARMS = [
+    // The 24-hour phishing blocklist refresh, retired when the runtime fetch
+    // was removed and the list became purely build-time vendored.
+    "autistmask-phishing-refresh",
+];
 
 const MIN_ALARM_PERIOD_MINUTES = 1;
 const BALANCE_REFRESH_PERIOD_MINUTES = 1;
-const PHISHING_REFRESH_PERIOD_MINUTES = 24 * 60;
 
 // alarmsApi() resolves on use rather than at module load: the worker is torn
 // down and re-evaluated repeatedly, and tests install a stub after requiring
@@ -65,22 +75,34 @@ async function ensureAlarm(name, periodInMinutes) {
 }
 
 /**
- * Ensure both recurring background jobs are scheduled. Safe to call on every
- * worker start, on onInstalled and on onStartup.
+ * Clear every alarm this extension no longer handles.
  *
- * @returns {Promise<{balance: boolean, phishing: boolean}>} which alarms this
- * call had to create.
+ * @returns {Promise<string[]>} the retired alarms this call actually cleared.
+ */
+async function clearObsoleteAlarms() {
+    const api = alarmsApi();
+    if (!api || !api.clear) return [];
+    const cleared = [];
+    for (const name of OBSOLETE_ALARMS) {
+        if (await api.clear(name)) cleared.push(name);
+    }
+    return cleared;
+}
+
+/**
+ * Ensure the recurring background jobs are scheduled, and that retired ones are
+ * not. Safe to call on every worker start, on onInstalled and on onStartup.
+ *
+ * @returns {Promise<{balance: boolean, cleared: string[]}>} which alarms this
+ * call had to create, and which retired ones it removed.
  */
 async function ensureRecurringAlarms() {
     const balance = await ensureAlarm(
         BALANCE_REFRESH_ALARM,
         BALANCE_REFRESH_PERIOD_MINUTES,
     );
-    const phishing = await ensureAlarm(
-        PHISHING_REFRESH_ALARM,
-        PHISHING_REFRESH_PERIOD_MINUTES,
-    );
-    return { balance, phishing };
+    const cleared = await clearObsoleteAlarms();
+    return { balance, cleared };
 }
 
 /**
@@ -102,10 +124,10 @@ function registerAlarmHandlers(handlers) {
 
 module.exports = {
     BALANCE_REFRESH_ALARM,
-    PHISHING_REFRESH_ALARM,
+    OBSOLETE_ALARMS,
     MIN_ALARM_PERIOD_MINUTES,
     BALANCE_REFRESH_PERIOD_MINUTES,
-    PHISHING_REFRESH_PERIOD_MINUTES,
+    clearObsoleteAlarms,
     ensureAlarm,
     ensureRecurringAlarms,
     registerAlarmHandlers,

src/shared/domainHash.js

@@ -0,0 +1,41 @@
+// The one definition of how a domain becomes a blocklist entry.
+//
+// The vendored phishing blocklist ships digests, not domain names: see
+// phishingDomains.js for why, and script/vendor-blocklist for how the artifact
+// is produced. Both sides have to agree exactly — a mismatch would silently
+// match nothing, which is a blocklist that quietly protects no one — so the
+// rule lives here and is required by both rather than written down twice.
+//
+// sha256 truncated to 64 bits. Truncation is what keeps the artifact small
+// enough to bundle (16 hex characters per entry rather than 64), and 64 bits is
+// far past what this has to withstand: over ~10^5 entries the chance that any
+// hostname a user visits collides with an entry it is not is about 10^-14 per
+// lookup, and a deliberate collision buys an attacker a false phishing warning
+// on a site they do not control, not a missed one. For scale, Safe Browsing
+// distributes 32-bit prefixes and resolves the rest against a server; this is
+// 32 bits more, with no server involved.
+
+const { sha256, toUtf8Bytes } = require("ethers");
+
+const HASH_ALGORITHM = "sha256";
+const HASH_HEX_CHARS = 16;
+
+/**
+ * The blocklist entry for a domain: lowercased, hashed, truncated.
+ *
+ * @param {string} domain
+ * @returns {string} HASH_HEX_CHARS lowercase hex characters, no 0x prefix.
+ */
+function hashDomain(domain) {
+    // ethers returns "0x" + 64 hex characters.
+    return sha256(toUtf8Bytes(domain.toLowerCase())).slice(
+        2,
+        2 + HASH_HEX_CHARS,
+    );
+}
+
+module.exports = {
+    HASH_ALGORITHM,
+    HASH_HEX_CHARS,
+    hashDomain,
+};

src/shared/ens.js

@@ -4,8 +4,7 @@
 //
 // POPUP ONLY. localStorage does not exist in the Chrome MV3 service worker,
 // so this module must not be pulled into src/background/. Anything the
-// background context needs to cache goes in extension storage instead (see
-// shared/phishingDomains.js).
+// background context needs to cache goes in extension storage instead.
 
 const { getProvider } = require("./balances");
 const { log } = require("./log");

src/shared/phishingDomains.js

@@ -1,158 +1,109 @@
-// Domain-based phishing detection using a vendored blocklist with delta updates.
+// Domain-based phishing detection against a blocklist vendored at build time.
 //
-// A community-maintained phishing domain blocklist is vendored in
-// phishingBlocklist.json and bundled at build time. At runtime, we fetch
-// the live list periodically and keep only the delta (new entries not in
-// the vendored list) in memory. This keeps runtime memory usage small.
+// The list is produced by script/vendor-blocklist from a hash-pinned upstream
+// commit, committed as phishingBlocklist.json, and bundled. There is no runtime
+// fetch: the extension asks nobody anything to answer this question, so no third
+// party learns which sites a user connects to, and no third party decides what
+// this wallet warns about. The cost is staleness — the shipped list is exactly
+// as fresh as the last vendoring run that was released — and the refresh path is
+// re-running that script and shipping the diff.
 //
-// The domain-checker checks the in-memory delta first (fresh/recent scam
-// sites), then falls back to the vendored list.
+// The artifact holds digests, not domains: sha256 truncated to 64 bits, one
+// entry per 16 hex characters, concatenated in sorted order into a single
+// string (see domainHash.js). Three things follow from that shape, and all
+// three are the reason for it:
 //
-// If the delta and its fetch timestamp fit in 256 KiB they are persisted to
-// extension storage, so they survive termination of the MV3 service worker.
-// Extension storage, not localStorage: localStorage does not exist in a
-// service worker, so the previous persistence never ran on Chrome at all.
-// The stored timestamps are what keep a restarted worker from re-fetching on
-// every wake while still noticing an overdue update. Those guards apply to the
-// startup path only; the 24-hour alarm tick bypasses them, or it would veto
-// its own refresh — see updatePhishingList().
+//   - the extension ships no plaintext list of anyone's domain names, which is
+//     what makes a blocklist assembled elsewhere shippable here at all.
+//   - a lookup is a binary search over that string. Nothing is built at module
+//     load, which matters because the MV3 service worker is torn down when idle
+//     and re-evaluates this file on every wake.
+//   - the file is 1.7 MB rather than 8.7 MB.
+//
+// Nothing here is async: callers answer an approval prompt with the result.
 
-const vendoredConfig = require("./phishingBlocklist.json");
-const { storageLocal } = require("./browserApi");
+const vendored = require("./phishingBlocklist.json");
+const { HASH_ALGORITHM, HASH_HEX_CHARS, hashDomain } = require("./domainHash");
 
-const BLOCKLIST_URL =
-    "https://raw.githubusercontent.com/MetaMask/eth-phishing-detect/main/src/config.json";
+// The artifact is generated, so a shape it does not have is a build fault, not
+// a runtime condition. It is checked anyway, and loudly, because every way of
+// getting it wrong — a stale format, a truncated file, a different digest —
+// produces a blocklist that matches nothing at all while looking perfectly
+// healthy. A phishing check that silently answers "no" to everything is the one
+// failure this module must not have.
+function checkArtifact(a) {
+    const bad = (why) =>
+        new Error(
+            "phishingBlocklist.json " +
+                why +
+                ". It is generated by script/vendor-blocklist; re-run that " +
+                "rather than editing it.",
+        );
 
-const CACHE_TTL_MS = 24 * 60 * 60 * 1000; // 24 hours
-
-// Floor on how often an unscheduled path may hit the network. The worker is
-// revived every ~30 seconds while the browser is busy, and every revival runs
-// the startup path; without a persisted record of the last attempt, any state
-// that leaves lastFetchTime unset — a fetch that failed, or a delta too large
-// to store — would download the full list on every single wake.
-const MIN_FETCH_ATTEMPT_INTERVAL_MS = 60 * 60 * 1000; // 1 hour
-
-const DELTA_STORAGE_KEY = "phishing-delta";
-const MAX_DELTA_BYTES = 256 * 1024; // 256 KiB
-
-// Vendored set — built once from the bundled JSON.
-const vendoredBlacklist = new Set(
-    (vendoredConfig.blacklist || []).map((d) => d.toLowerCase()),
-);
-
-// Delta set — only entries from live list that are NOT in vendored.
-let deltaBlacklist = new Set();
-let lastFetchTime = 0;
-let lastAttemptTime = 0;
-let fetchPromise = null;
-let loadPromise = null;
-
-// storageLocal() resolves on use rather than at module load, so a test can
-// install a stub after requiring this module, and it returns null where the
-// API is absent — which is why the popup, with no reason to touch the delta,
-// loads fine without it.
-
-/**
- * Sanitise a timestamp read back from storage.
- *
- * A value in the future is permanent poison: every guard here measures elapsed
- * time as `Date.now() - stamp` and tests only the lower bound, so a stamp a
- * year ahead suppresses updates for a year with no path that ever clears it.
- * Clock skew and a restored profile backup both produce one. Since these
- * timestamps only ever gate work, discarding an impossible one is safe: it
- * costs at most a single extra fetch and restores a sane value immediately.
- *
- * @param {unknown} value
- * @returns {number} the timestamp, or 0 if it is unusable.
- */
-function sanitizeTimestamp(value) {
-    if (typeof value !== "number" || !Number.isFinite(value)) return 0;
-    if (value <= 0 || value > Date.now()) return 0;
-    return value;
-}
-
-/**
- * Load the persisted delta and its timestamps from extension storage.
- * Runs once per worker lifetime; every entry point funnels through
- * ensureDeltaLoaded() so a wake from termination restores state exactly once.
- *
- * @returns {Promise<void>}
- */
-async function loadDeltaFromStorage() {
-    const storage = storageLocal();
-    if (!storage) return;
-    try {
-        const result = await storage.get(DELTA_STORAGE_KEY);
-        const data = result && result[DELTA_STORAGE_KEY];
-        if (!data) return;
-        if (Array.isArray(data.blacklist)) {
-            deltaBlacklist = new Set(
-                data.blacklist.map((d) => d.toLowerCase()),
-            );
-        }
-        lastFetchTime = sanitizeTimestamp(data.lastFetchTime);
-        lastAttemptTime = sanitizeTimestamp(data.lastAttemptTime);
-    } catch {
-        // Storage unavailable or corrupt — start empty and re-fetch.
+    if (!a || typeof a !== "object") throw bad("is not an object");
+    if (a.algorithm !== HASH_ALGORITHM) {
+        throw bad(
+            "declares algorithm " +
+                JSON.stringify(a.algorithm) +
+                ", but this build hashes with " +
+                HASH_ALGORITHM,
+        );
+    }
+    if (a.hashHexChars !== HASH_HEX_CHARS) {
+        throw bad(
+            "declares " +
+                JSON.stringify(a.hashHexChars) +
+                " hex characters per entry, but this build produces " +
+                HASH_HEX_CHARS,
+        );
+    }
+    if (typeof a.hashes !== "string") throw bad("has no hashes string");
+    if (!Number.isInteger(a.count) || a.count < 1) {
+        throw bad("declares no usable entry count");
+    }
+    if (a.hashes.length !== a.count * HASH_HEX_CHARS) {
+        throw bad(
+            "holds " +
+                a.hashes.length +
+                " hex characters, which is not the " +
+                a.count * HASH_HEX_CHARS +
+                " its count of " +
+                a.count +
+                " entries requires",
+        );
     }
 }
 
-function ensureDeltaLoaded() {
-    if (!loadPromise) loadPromise = loadDeltaFromStorage();
-    return loadPromise;
-}
+checkArtifact(vendored);
+
+const HASHES = vendored.hashes;
+const COUNT = vendored.count;
 
 /**
- * Persist the delta and its timestamps if they fit within MAX_DELTA_BYTES.
+ * Is this digest one of the vendored entries?
  *
- * The 256 KiB cap covers the delta and its freshness claim: when the delta is
- * too large to keep, lastFetchTime goes with it, so the next start re-fetches
- * rather than trusting a freshness claim for a delta it no longer holds.
- * lastAttemptTime is written either way — it records that the network was
- * contacted, which stays true whatever became of the response, and it is what
- * stops a permanently oversized list from downloading on every worker wake.
+ * Binary search over fixed-width records. The digests are lowercase hex of one
+ * width, so lexicographic order is numeric order and the artifact is written
+ * sorted; tests assert that ordering against the committed file, because an
+ * unsorted artifact would fail lookups silently rather than loudly.
  *
- * @returns {Promise<void>}
+ * @param {string} hash
+ * @returns {boolean}
  */
-async function saveDeltaToStorage() {
-    const storage = storageLocal();
-    if (!storage) return;
-    try {
-        const data = {
-            blacklist: Array.from(deltaBlacklist),
-            lastFetchTime,
-            lastAttemptTime,
-        };
-        const json = JSON.stringify(data);
-        if (json.length < MAX_DELTA_BYTES) {
-            await storage.set({ [DELTA_STORAGE_KEY]: data });
-        } else if (lastAttemptTime > 0) {
-            await storage.set({ [DELTA_STORAGE_KEY]: { lastAttemptTime } });
-        } else {
-            await storage.remove(DELTA_STORAGE_KEY);
-        }
-    } catch {
-        // Storage unavailable — skip silently
+function hashListed(hash) {
+    let lo = 0;
+    let hi = COUNT - 1;
+    while (lo <= hi) {
+        const mid = (lo + hi) >> 1;
+        const at = HASHES.slice(
+            mid * HASH_HEX_CHARS,
+            (mid + 1) * HASH_HEX_CHARS,
+        );
+        if (at === hash) return true;
+        if (at < hash) lo = mid + 1;
+        else hi = mid - 1;
     }
-}
-
-/**
- * Load a pre-parsed config and compute the delta against the vendored list.
- * Used for both live fetches and testing.
- *
- * @param {{ blacklist?: string[] }} config
- * @returns {Promise<void>} resolves once the delta has been persisted.
- */
-function loadConfig(config) {
-    const liveBlacklist = (config.blacklist || []).map((d) => d.toLowerCase());
-
-    // Delta = entries in the live list that are NOT in the vendored list
-    deltaBlacklist = new Set(
-        liveBlacklist.filter((d) => !vendoredBlacklist.has(d)),
-    );
-
-    lastFetchTime = Date.now();
-    return saveDeltaToStorage();
+    return false;
 }
 
 /**
@@ -175,161 +126,33 @@ function hostnameVariants(hostname) {
 
 /**
  * Check if a hostname is on the phishing blocklist.
- * Checks delta first (fresh/recent scam sites), then vendored list.
- *
- * Synchronous by design — callers answer an approval prompt with it. On a
- * worker that has just woken, the persisted delta may still be loading; the
- * vendored list, which is bundled and always present, carries the check until
- * it lands.
  *
  * @param {string} hostname - The hostname to check.
  * @returns {boolean}
  */
 function isPhishingDomain(hostname) {
     if (!hostname) return false;
-    const variants = hostnameVariants(hostname);
-
-    // Check delta blacklist first (fresh/recent scam sites), then vendored
-    for (const v of variants) {
-        if (deltaBlacklist.has(v) || vendoredBlacklist.has(v)) return true;
+    for (const variant of hostnameVariants(hostname)) {
+        if (hashListed(hashDomain(variant))) return true;
     }
     return false;
 }
 
 /**
- * Fetch the latest blocklist and compute delta against vendored data.
- * De-duplicates concurrent fetches. Results are cached for CACHE_TTL_MS,
- * counted from the persisted timestamp so the cache outlives the worker.
- *
- * `force` is what makes the 24-hour alarm actually refresh every 24 hours.
- * The alarm fires one period after the previous alarm, but lastFetchTime is
- * stamped when that fetch *completed*, so an unforced tick lands one fetch
- * latency inside its own TTL, skips, and turns the real cadence into 48 hours.
- * Shortening the TTL instead would not fix it: the worker wakes every ~30
- * seconds and the startup path re-checks the TTL each time, so a shortened TTL
- * simply becomes the real cadence. The TTL is there to stop redundant fetches
- * on wake, and the scheduled tick is not redundant, so it bypasses it.
- *
- * @param {{force?: boolean}} [opts] force: fetch unless one is already in
- * flight, ignoring both the freshness and the retry guard. For the scheduled
- * alarm tick only.
- * @returns {Promise<void>}
- */
-async function updatePhishingList({ force = false } = {}) {
-    // A worker that has just been revived knows nothing until the persisted
-    // record is back in memory; without this the freshness check below would
-    // always see 0 and re-fetch on every wake.
-    await ensureDeltaLoaded();
-
-    if (!force) {
-        const now = Date.now();
-        // Skip if recently fetched.
-        if (lastFetchTime > 0 && now - lastFetchTime < CACHE_TTL_MS) return;
-        // Skip if the network was contacted recently and the result was not
-        // usable — a failed fetch or an oversized delta leaves lastFetchTime
-        // unset, and without this every wake would retry.
-        if (
-            lastAttemptTime > 0 &&
-            now - lastAttemptTime < MIN_FETCH_ATTEMPT_INTERVAL_MS
-        ) {
-            return;
-        }
-    }
-
-    // De-duplicate concurrent calls
-    if (fetchPromise) return fetchPromise;
-
-    fetchPromise = (async () => {
-        lastAttemptTime = Date.now();
-        try {
-            const resp = await fetch(BLOCKLIST_URL);
-            if (!resp.ok) throw new Error("HTTP " + resp.status);
-            const config = await resp.json();
-            await loadConfig(config);
-        } catch {
-            // Silently fail — vendored list still provides coverage. Persist
-            // the attempt so a persistently failing fetch is retried on the
-            // schedule rather than on every wake.
-            await saveDeltaToStorage();
-        } finally {
-            fetchPromise = null;
-        }
-    })();
-
-    return fetchPromise;
-}
-
-/**
- * Restore persisted state and fetch if the list is overdue.
- *
- * Called from the background script every time it starts — a fresh install,
- * a browser start, and every revival of a terminated service worker all land
- * here. The recurring 24-hour schedule itself is an alarm (see
- * shared/alarms.js), not a timer, because timers die with the worker.
- *
- * @returns {Promise<void>}
- */
-async function initPhishingList() {
-    await ensureDeltaLoaded();
-    return updatePhishingList();
-}
-
-/**
- * The 24-hour alarm tick. Separate from initPhishingList() because this is the
- * scheduled refresh and must not be vetoed by the guards that exist to keep
- * the unscheduled startup path off the network.
- *
- * @returns {Promise<void>}
- */
-async function refreshPhishingListOnSchedule() {
-    return updatePhishingList({ force: true });
-}
-
-/**
- * Return the total blocklist size (vendored + delta) for diagnostics.
+ * Return the blocklist size for diagnostics.
  *
  * @returns {number}
  */
 function getBlocklistSize() {
-    return vendoredBlacklist.size + deltaBlacklist.size;
-}
-
-/**
- * Return the delta blocklist size for diagnostics.
- *
- * @returns {number}
- */
-function getDeltaSize() {
-    return deltaBlacklist.size;
-}
-
-/**
- * Reset internal state (for testing).
- */
-function _reset() {
-    deltaBlacklist = new Set();
-    lastFetchTime = 0;
-    lastAttemptTime = 0;
-    fetchPromise = null;
-    loadPromise = null;
+    return COUNT;
 }
 
 module.exports = {
     isPhishingDomain,
-    updatePhishingList,
-    refreshPhishingListOnSchedule,
-    initPhishingList,
-    loadDeltaFromStorage,
-    loadConfig,
-    CACHE_TTL_MS,
-    MIN_FETCH_ATTEMPT_INTERVAL_MS,
-    DELTA_STORAGE_KEY,
-    MAX_DELTA_BYTES,
     getBlocklistSize,
-    getDeltaSize,
     hostnameVariants,
-    _reset,
-    // Exposed for testing only
-    _getVendoredBlacklistSize: () => vendoredBlacklist.size,
-    _getDeltaBlacklist: () => deltaBlacklist,
+    // Exposed for testing only: the ends of the search range are where an
+    // off-by-one hides, and reaching them through isPhishingDomain() would mean
+    // knowing which domain hashes to the first or last entry.
+    _hashListed: hashListed,
 };