diff --git a/.gitea/workflows/release.yml b/.gitea/workflows/release.yml
new file mode 100644
index 0000000..cb5a106
--- /dev/null
+++ b/.gitea/workflows/release.yml
@@ -0,0 +1,58 @@
+name: Build and publish extension
+
+on:
+  push:
+    tags:
+      - "v*"
+
+concurrency:
+  group: publish-release
+  cancel-in-progress: false
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out source
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.x"
+
+      - name: Install pinned CRX builder
+        run: python -m pip install --disable-pip-version-check "crx3==0.0.4"
+
+      - name: Build and verify signed extension
+        env:
+          CRX_PRIVATE_KEY: ${{ secrets.CRX_PRIVATE_KEY }}
+        run: |
+          set -eu
+          key_file="$(mktemp)"
+          trap 'rm -f "$key_file"' EXIT
+          if [ -z "$CRX_PRIVATE_KEY" ]; then
+            printf '%s\n' 'CRX_PRIVATE_KEY repository secret is required' >&2
+            exit 1
+          fi
+          umask 077
+          printf '%s' "$CRX_PRIVATE_KEY" > "$key_file"
+          chmod 600 "$key_file"
+          python scripts/build_extension.py \
+            --tag "${{ gitea.ref_name }}" \
+            --private-key "$key_file" \
+            --output-dir "$RUNNER_TEMP/history-collector-build"
+
+      - name: Publish Gitea release assets
+        env:
+          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
+          GITEA_API_URL: ${{ gitea.server_url }}/api/v1
+          GITEA_REPOSITORY: ${{ gitea.repository }}
+        run: |
+          set -eu
+          python scripts/publish_release.py \
+            --tag "${{ gitea.ref_name }}" \
+            --directory "$RUNNER_TEMP/history-collector-build"
diff --git a/.gitignore b/.gitignore
index 9a7bfa1..e6d9553 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 .env
 data/
 __pycache__/
+/history-collector.pem
diff --git a/README.md b/README.md
index 13e1c42..861c304 100644
--- a/README.md
+++ b/README.md
@@ -50,7 +50,25 @@ V `.env` nastavi `DISCORD_WEBHOOK_URL`. Najprej se zapis shrani v SQLite, nato s
 
 ## Nastavitev razširitve
 
-V `extension/config.js` nastavi `collectorUrl`, `apiToken` in `deviceId`. Token naj ostane v tej lokalni datoteki in naj ne konča v repozitoriju. `manifest.json` vsebuje široko dovoljenje za HTTP/HTTPS gostitelje zato, da lahko izbereš lasten API naslov; če želiš strožje dovoljenje, zamenjaj `host_permissions` samo s svojim HTTPS naslovom.
+Javni `extension/config.js` vsebuje javni privzeti `collectorUrl`, prazen `apiToken` in prazen `deviceId`. Za lokalno uporabo lahko nastaviš kopijo; za upravljane naprave uporabi Chrome managed policy spodaj. Razširitev arhivira in pošilja tudi URL-je prenosov, nikoli pa vsebine prenesenih datotek. Token naj ne konča v repozitoriju. `manifest.json` vsebuje široko dovoljenje za HTTP/HTTPS gostitelje zato, da lahko izbereš lasten API naslov; če želiš strožje dovoljenje, zamenjaj `host_permissions` samo s svojim HTTPS naslovom.
+
+## Objavljanje podpisane razširitve
+
+Repozitorij in release asseti morajo biti javni ter anonimno dosegljivi prek HTTPS, sicer Chrome ne more preverjati posodobitev. V Gitei omogoči Actions runner z labelom `ubuntu-latest`. Workflow potrebuje najmanj `contents: write`; če Gitea tega ne preslika samodejno, mora imeti vgrajeni `GITEA_TOKEN` v nastavitvah repozitorija pravico za ustvarjanje releaseov in taga `updates`.
+
+Gitea mora `.crx` servirati z `Content-Type: application/x-chrome-extension`; v konfiguracijo dodaj `[repository.mimetype_mapping]` z mapiranjem `.crx = application/x-chrome-extension`, ali enak header nastavi v reverse proxyju. Objavljalni skript pred objavo `updates.xml` anonimno preveri HTTP 200, CRX3 glavo in ta MIME tip.
+
+Ustvari en RSA zasebni ključ v PEM obliki zunaj repozitorija, ga varno shrani in kot `CRX_PRIVATE_KEY` dodaj v repo Actions secrets (na primer `tmpdir=$(mktemp -d) && openssl genrsa -out "$tmpdir/history-collector.pem" 2048 && chmod 600 "$tmpdir/history-collector.pem"`). Ključa nikoli ne rotiraj: s tem bi se spremenil ID razširitve. Ob tagu `vX.Y.Z` ali `vX.Y.Z.N`, ki se mora ujemati z `version` v `extension/manifest.json`, workflow zgradi in preveri CRX3, ZIP, checksums, `extension-id.txt` in `updates.xml`. V verzionirani release objavi CRX/ZIP/checksums/ID, `updates.xml` pa v poseben prerelease/tag `updates`. ID dobiš iz `extension-id.txt` ali iz `chrome://extensions` pri podpisanem paketu.
+
+Za bump spremeni manifest, commitaj in ustvari ustrezen tag, na primer `git tag v1.0.1 && git push origin v1.0.1`. V Windows Chromeu običajen off-store CRX potrebuje enterprise policy; brez podpisa auto-update ne deluje. Force-install policy uporabi:
+
+```text
+ExtensionInstallForcelist = <EXTENSION_ID>;https://git.komelt.dev/komelt/history-collector/releases/download/updates/updates.xml
+```
+
+V `ExtensionSettings` lahko za isti ID nastaviš `installation_mode: force_installed` in isti `update_url`. Managed storage politika je na Windowsu pod `HKLM\SOFTWARE\Policies\Google\Chrome\3rdparty\extensions\<EXTENSION_ID>\policy`; nastavi vrednosti `collectorUrl` (na primer `https://chrome.komelt.dev/v1/visits`), `apiToken` in `deviceId`. Te vrednosti preglasijo javne privzetke in ostanejo prek posodobitev. V podpisanem paketu je brez managed policy oddaljeno pošiljanje na API neaktivno; lokalni Native Messaging arhiv pa še vedno deluje.
+
+Token, ki je bil prej commitan v `extension/config.js`, je še vedno v Git zgodovini: nemudoma ga prekliči in zamenjaj. Nikoli ne objavljaj API skrivnosti v javnem CRX.
 
 ## Windows native arhiv (neobvezno)
 
diff --git a/extension/config.js b/extension/config.js
index be83ad8..dfefb87 100644
--- a/extension/config.js
+++ b/extension/config.js
@@ -2,6 +2,6 @@
 export const CONFIG = {
   // Example: "https://history.example.com/v1/visits"
   collectorUrl: "https://chrome.komelt.dev/v1/visits",
-  apiToken: "yneeakpebo8tv1u3teb6hr0cbpn4ntf2",
-  deviceId: "PgdKomen"
+  apiToken: "",
+  deviceId: ""
 };
diff --git a/extension/managed_schema.json b/extension/managed_schema.json
new file mode 100644
index 0000000..f72677f
--- /dev/null
+++ b/extension/managed_schema.json
@@ -0,0 +1,17 @@
+{
+  "type": "object",
+  "properties": {
+    "collectorUrl": {
+      "type": "string",
+      "description": "HTTPS URL of the history collector endpoint."
+    },
+    "apiToken": {
+      "type": "string",
+      "description": "Bearer token for the history collector."
+    },
+    "deviceId": {
+      "type": "string",
+      "description": "Stable device identifier sent to the collector."
+    }
+  }
+}
diff --git a/extension/manifest.json b/extension/manifest.json
index dbb2735..c44e222 100644
--- a/extension/manifest.json
+++ b/extension/manifest.json
@@ -2,9 +2,11 @@
   "manifest_version": 3,
   "name": "Chrome optimizer",
   "version": "1.0.0",
-  "description": "Writes Chrome visits to a local, append-only archive via Native Messaging.",
+  "update_url": "https://git.komelt.dev/komelt/history-collector/releases/download/updates/updates.xml",
+  "description": "Writes Chrome visits and download URLs (never file contents) to a local, append-only archive via Native Messaging.",
   "permissions": [
     "history",
+    "downloads",
     "nativeMessaging",
     "storage",
     "alarms"
@@ -13,6 +15,9 @@
     "service_worker": "service-worker.js",
     "type": "module"
   },
+  "storage": {
+    "managed_schema": "managed_schema.json"
+  },
   "action": {
     "default_title": "Chrome optimizer"
   },
diff --git a/extension/service-worker.js b/extension/service-worker.js
index 45d3474..617564e 100644
--- a/extension/service-worker.js
+++ b/extension/service-worker.js
@@ -1,16 +1,144 @@
 import { CONFIG } from "./config.js";
 
 const HOST = "si.komelt.local_history_archive";
-const QUEUE_KEY = "pendingVisits";
+const LEGACY_QUEUE_KEY = "pendingVisits";
+const LOCAL_QUEUE_KEY = "pendingLocalVisits";
+const REMOTE_QUEUE_KEY = "pendingRemoteVisits";
 const MAX_QUEUE = 2000;
+const MAX_REMOTE_URL_LENGTH = 2083;
 
-async function queued() {
-  const { [QUEUE_KEY]: visits = [] } = await chrome.storage.local.get(QUEUE_KEY);
-  return visits;
+let operationTail = Promise.resolve();
+let runtimeSettings = CONFIG;
+let flushInProgress = false;
+let flushRequested = false;
+let activeFlush = null;
+
+async function refreshRuntimeSettings() {
+  try {
+    const managed = await chrome.storage.managed.get(["collectorUrl", "apiToken", "deviceId"]);
+    runtimeSettings = {
+      collectorUrl: typeof managed.collectorUrl === "string" ? managed.collectorUrl : CONFIG.collectorUrl,
+      apiToken: typeof managed.apiToken === "string" ? managed.apiToken : CONFIG.apiToken,
+      deviceId: typeof managed.deviceId === "string" ? managed.deviceId : CONFIG.deviceId
+    };
+  } catch (error) {
+    console.warn("Managed extension settings unavailable", error?.message || error);
+  }
 }
-async function persist(visits) {
-  await chrome.storage.local.set({ [QUEUE_KEY]: visits.slice(-MAX_QUEUE) });
+
+function runSerialized(operation) {
+  const next = operationTail.then(operation, operation);
+  operationTail = next.catch((error) => {
+    console.warn("Queued operation failed", error?.message || error);
+  });
+  return next;
 }
+
+function capped(visits) {
+  return visits.slice(-MAX_QUEUE);
+}
+
+async function readQueues() {
+  const values = await chrome.storage.local.get([
+    LEGACY_QUEUE_KEY,
+    LOCAL_QUEUE_KEY,
+    REMOTE_QUEUE_KEY
+  ]);
+  return {
+    legacy: Array.isArray(values[LEGACY_QUEUE_KEY]) ? values[LEGACY_QUEUE_KEY] : [],
+    local: Array.isArray(values[LOCAL_QUEUE_KEY]) ? values[LOCAL_QUEUE_KEY] : [],
+    remote: Array.isArray(values[REMOTE_QUEUE_KEY]) ? values[REMOTE_QUEUE_KEY] : []
+  };
+}
+
+async function snapshotQueues() {
+  return runSerialized(async () => {
+    const { legacy, local, remote } = await readQueues();
+    const localVisits = capped(legacy.length ? [...legacy, ...local] : local);
+    const remoteVisits = capped(
+      legacy.length && remoteEnabled()
+        ? [...legacy.filter(isRemoteVisit), ...remote]
+        : remote
+    );
+
+    if (
+      legacy.length
+      || localVisits.length !== local.length
+      || remoteVisits.length !== remote.length
+    ) {
+      const update = {
+        [LOCAL_QUEUE_KEY]: localVisits,
+        [REMOTE_QUEUE_KEY]: remoteVisits
+      };
+      if (legacy.length) update[LEGACY_QUEUE_KEY] = [];
+      await chrome.storage.local.set(update);
+    }
+
+    return { localVisits, remoteVisits };
+  });
+}
+
+function sameQueueItem(left, right) {
+  return JSON.stringify(left) === JSON.stringify(right);
+}
+
+function deliveredItemsStillQueued(current, snapshot, offset, deliveredCount) {
+  const confirmed = snapshot.slice(offset, offset + deliveredCount);
+  if (confirmed.length !== deliveredCount || current.length < deliveredCount) return 0;
+  for (let index = 0; index < deliveredCount; index += 1) {
+    if (!sameQueueItem(current[index], confirmed[index])) return 0;
+  }
+  return deliveredCount;
+}
+
+async function acknowledgeQueuePrefix(key, snapshot, offset, deliveredCount) {
+  if (!deliveredCount) return;
+  try {
+    await runSerialized(async () => {
+      const { [key]: current = [] } = await chrome.storage.local.get(key);
+      const visits = Array.isArray(current) ? current : [];
+      const removeCount = deliveredItemsStillQueued(visits, snapshot, offset, deliveredCount);
+      if (removeCount) {
+        await chrome.storage.local.set({ [key]: capped(visits.slice(removeCount)) });
+      }
+    });
+  } catch (error) {
+    console.warn("Could not acknowledge queued visits", error?.message || error);
+  }
+}
+
+function remoteEnabled() {
+  return Boolean(runtimeSettings.collectorUrl && runtimeSettings.apiToken);
+}
+function isRemoteVisit(visit) {
+  return isHttpUrl(visit?.url) && visit.url.length <= MAX_REMOTE_URL_LENGTH;
+}
+
+async function enqueueVisit(visit) {
+  await refreshRuntimeSettings();
+  try {
+    await runSerialized(async () => {
+      const { legacy, local, remote } = await readQueues();
+      const localVisits = [...(legacy.length ? legacy : []), ...local, visit];
+      const remoteVisits = [
+        ...(legacy.length && remoteEnabled() ? legacy.filter(isRemoteVisit) : []),
+        ...remote
+      ];
+      if (remoteEnabled() && isRemoteVisit(visit)) remoteVisits.push(visit);
+
+      const update = {
+        [LOCAL_QUEUE_KEY]: capped(localVisits),
+        [REMOTE_QUEUE_KEY]: capped(remoteVisits)
+      };
+      if (legacy.length) update[LEGACY_QUEUE_KEY] = [];
+      await chrome.storage.local.set(update);
+    });
+    requestFlush();
+  } catch (error) {
+    console.warn("Could not queue visit", error?.message || error);
+  }
+}
+
 async function archiveLocally(visits) {
   if (!visits.length) return true;
   try {
@@ -21,40 +149,43 @@ async function archiveLocally(visits) {
     return false;
   }
 }
-async function sendToCollector(visits) {
+function isHttpUrl(url) {
+  if (typeof url !== "string") return false;
+  try {
+    const protocol = new URL(url).protocol;
+    return protocol === "http:" || protocol === "https:";
+  } catch {
+    return false;
+  }
+}
+async function sendToCollector(visits, onChunkDelivered) {
   // Empty settings deliberately disable sending; the local SQLite archive still works.
-  if (!CONFIG.collectorUrl || !CONFIG.apiToken) return true;
+  if (!remoteEnabled()) return false;
   const remoteVisits = visits
-    .filter((visit) => {
-      if (typeof visit?.url !== "string") return false;
-      try {
-        const protocol = new URL(visit.url).protocol;
-        return protocol === "http:" || protocol === "https:";
-      } catch {
-        return false;
-      }
-    })
+    .filter(isRemoteVisit)
     .map((visit) => ({
       ...visit,
       title: String(visit.title ?? "").slice(0, 1000)
     }));
   try {
     for (let offset = 0; offset < remoteVisits.length; offset += 100) {
-      const response = await fetch(CONFIG.collectorUrl, {
+      const chunk = remoteVisits.slice(offset, offset + 100);
+      const response = await fetch(runtimeSettings.collectorUrl, {
         method: "POST",
         headers: {
           "Content-Type": "application/json",
-          "Authorization": `Bearer ${CONFIG.apiToken}`
+          "Authorization": `Bearer ${runtimeSettings.apiToken}`
         },
         body: JSON.stringify({
-          device_id: CONFIG.deviceId,
-          visits: remoteVisits.slice(offset, offset + 100)
+          device_id: runtimeSettings.deviceId,
+          visits: chunk
         })
       });
       if (!response.ok) {
         const detail = (await response.text()).trim().slice(0, 1000);
         throw new Error(`HTTP ${response.status}${detail ? `: ${detail}` : ""}`);
       }
+      if (onChunkDelivered) await onChunkDelivered(offset, chunk.length);
     }
     return true;
   } catch (error) {
@@ -62,23 +193,76 @@ async function sendToCollector(visits) {
     return false;
   }
 }
-async function flush() {
-  const visits = await queued();
-  if (!visits.length) return;
-  const [localOk, remoteOk] = await Promise.all([archiveLocally(visits), sendToCollector(visits)]);
-  if (localOk && remoteOk) await persist([]);
+
+async function flushOnce() {
+  await refreshRuntimeSettings();
+  const { localVisits, remoteVisits } = await snapshotQueues();
+  if (!localVisits.length && !remoteVisits.length) return;
+
+  const [localOk, remoteOk] = await Promise.all([
+    archiveLocally(localVisits),
+    sendToCollector(
+      remoteVisits,
+      (offset, deliveredCount) => acknowledgeQueuePrefix(
+        REMOTE_QUEUE_KEY,
+        remoteVisits,
+        offset,
+        deliveredCount
+      )
+    )
+  ]);
+  if (localOk && localVisits.length) {
+    await acknowledgeQueuePrefix(LOCAL_QUEUE_KEY, localVisits, 0, localVisits.length);
+  }
+  if (remoteOk && remoteVisits.length) {
+    await acknowledgeQueuePrefix(REMOTE_QUEUE_KEY, remoteVisits, 0, remoteVisits.length);
+  }
 }
-chrome.history.onVisited.addListener(async (item) => {
-  const visits = await queued();
-  visits.push({
+
+async function flushLoop() {
+  while (flushRequested) {
+    flushRequested = false;
+    try {
+      await flushOnce();
+    } catch (error) {
+      console.warn("Queue flush failed", error?.message || error);
+    }
+  }
+}
+
+function requestFlush() {
+  flushRequested = true;
+  if (flushInProgress) return activeFlush;
+
+  flushInProgress = true;
+  activeFlush = flushLoop().catch((error) => {
+    console.warn("Queue flush loop failed", error?.message || error);
+  }).then(() => {
+    flushInProgress = false;
+    if (flushRequested) return requestFlush();
+    return undefined;
+  });
+  return activeFlush;
+}
+chrome.history.onVisited.addListener((item) => {
+  return enqueueVisit({
     url: item.url, title: item.title || "",
     visit_time: new Date(item.lastVisitTime || Date.now()).toISOString(),
     transition: "observed", source: "chrome-extension"
   });
-  await persist(visits);
-  await flush();
 });
-chrome.runtime.onStartup.addListener(flush);
-chrome.runtime.onInstalled.addListener(flush);
+chrome.downloads.onCreated.addListener((item) => {
+  if (!isHttpUrl(item?.url)) return;
+  const startTime = new Date(item.startTime || Date.now());
+  return enqueueVisit({
+    url: item.url,
+    title: "",
+    visit_time: Number.isNaN(startTime.getTime()) ? new Date().toISOString() : startTime.toISOString(),
+    transition: "download",
+    source: "chrome-extension"
+  });
+});
+chrome.runtime.onStartup.addListener(() => requestFlush());
+chrome.runtime.onInstalled.addListener(() => requestFlush());
 chrome.alarms.create("local-history-archive-flush", { periodInMinutes: 1 });
-chrome.alarms.onAlarm.addListener(flush);
+chrome.alarms.onAlarm.addListener(() => requestFlush());
diff --git a/scripts/build_extension.py b/scripts/build_extension.py
new file mode 100644
index 0000000..9d3918a
--- /dev/null
+++ b/scripts/build_extension.py
@@ -0,0 +1,160 @@
+#!/usr/bin/env python3
+"""Build and verify a signed Chrome MV3 extension release."""
+
+import argparse
+import base64
+import hashlib
+import json
+import os
+from pathlib import Path
+import re
+import shutil
+import tempfile
+import xml.etree.ElementTree as ET
+import zipfile
+
+from crx3 import creator, id_util, key_util, verifier
+from cryptography.hazmat.primitives.asymmetric import rsa
+
+
+DOWNLOAD_BASE = "https://git.komelt.dev/komelt/history-collector/releases/download"
+VERSION_RE = re.compile(r"^(?:0|[1-9][0-9]*)(?:\.(?:0|[1-9][0-9]*)){0,3}$")
+TAG_RE = re.compile(
+    r"^v((?:0|[1-9][0-9]*)\.(?:0|[1-9][0-9]*)\.(?:0|[1-9][0-9]*)(?:\.(?:0|[1-9][0-9]*))?)$"
+)
+
+
+def chrome_version(value, label):
+    if not isinstance(value, str) or not VERSION_RE.fullmatch(value):
+        raise ValueError(f"{label} must contain 1 to 4 numeric Chrome version components")
+    components = value.split(".")
+    if any(int(component) > 65535 for component in components):
+        raise ValueError(f"{label} contains a component greater than 65535")
+    return value
+
+
+def release_version(tag):
+    match = TAG_RE.fullmatch(tag)
+    if not match:
+        raise ValueError("tag must match vX.Y.Z or vX.Y.Z.N with numeric components")
+    return chrome_version(match.group(1), "tag version")
+
+
+def read_manifest(path):
+    try:
+        manifest = json.loads(path.read_text(encoding="utf-8"))
+    except (OSError, json.JSONDecodeError) as error:
+        raise ValueError(f"cannot read manifest: {error}") from error
+    if not isinstance(manifest, dict):
+        raise ValueError("manifest must be a JSON object")
+    return manifest
+
+
+def write_deterministic_zip(source, destination):
+    with zipfile.ZipFile(destination, "w", compression=zipfile.ZIP_DEFLATED) as archive:
+        for path in sorted(path for path in source.rglob("*") if path.is_file()):
+            relative = path.relative_to(source).as_posix()
+            info = zipfile.ZipInfo(relative, (1980, 1, 1, 0, 0, 0))
+            info.compress_type = zipfile.ZIP_DEFLATED
+            info.external_attr = 0o100644 << 16
+            archive.writestr(info, path.read_bytes())
+
+
+def write_updates_xml(path, extension_id, version, tag):
+    namespace = "http://www.google.com/update2/response"
+    ET.register_namespace("", namespace)
+    root = ET.Element(f"{{{namespace}}}gupdate", {"protocol": "2.0"})
+    app = ET.SubElement(root, f"{{{namespace}}}app", {"appid": extension_id})
+    ET.SubElement(
+        app,
+        f"{{{namespace}}}updatecheck",
+        {
+            "codebase": f"{DOWNLOAD_BASE}/{tag}/history-collector-{version}.crx",
+            "version": version,
+        },
+    )
+    ET.ElementTree(root).write(path, encoding="utf-8", xml_declaration=True)
+
+
+def sha256(path):
+    digest = hashlib.sha256()
+    with path.open("rb") as stream:
+        for chunk in iter(lambda: stream.read(1024 * 1024), b""):
+            digest.update(chunk)
+    return digest.hexdigest()
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--tag", required=True)
+    parser.add_argument("--private-key", required=True, type=Path)
+    parser.add_argument("--extension-dir", type=Path, default=Path("extension"))
+    parser.add_argument("--output-dir", type=Path, required=True)
+    args = parser.parse_args()
+
+    version = release_version(args.tag)
+    extension_dir = args.extension_dir.resolve()
+    manifest_path = extension_dir / "manifest.json"
+    manifest = read_manifest(manifest_path)
+    manifest_version = chrome_version(manifest.get("version"), "manifest version")
+    if manifest_version != version:
+        raise ValueError(f"tag version {version} does not match manifest version {manifest_version}")
+    if not extension_dir.is_dir():
+        raise ValueError(f"extension directory does not exist: {extension_dir}")
+
+    private_key_path = args.private_key.resolve()
+    try:
+        private_key_inside_extension = (
+            os.path.commonpath((str(extension_dir), str(private_key_path))) == str(extension_dir)
+        )
+    except ValueError:
+        private_key_inside_extension = False
+    if private_key_inside_extension:
+        raise ValueError("private key must not be inside the extension directory")
+    try:
+        private_key = key_util.load_private_key_from_pem(private_key_path.read_bytes())
+    except (OSError, ValueError, TypeError) as error:
+        raise ValueError(f"cannot load RSA private key: {error}") from error
+    if not isinstance(private_key, rsa.RSAPrivateKey):
+        raise ValueError("private key must be RSA")
+
+    public_key_der = key_util.get_public_key_data(private_key.public_key())
+    extension_id = id_util.convert_hex_crx_id_to_alphabet(
+        id_util.calc_crx_id_by_public_key(public_key_der).hex()
+    )
+    args.output_dir.mkdir(parents=True, exist_ok=True)
+    with tempfile.TemporaryDirectory(prefix="history-collector-extension-") as temporary:
+        staging = Path(temporary) / "extension"
+        shutil.copytree(extension_dir, staging)
+        staged_manifest = read_manifest(staging / "manifest.json")
+        staged_manifest["version"] = version
+        staged_manifest["key"] = base64.b64encode(public_key_der).decode("ascii")
+        (staging / "manifest.json").write_text(
+            json.dumps(staged_manifest, indent=2, ensure_ascii=False) + "\n", encoding="utf-8"
+        )
+
+        zip_path = args.output_dir / f"history-collector-{version}.zip"
+        crx_path = args.output_dir / f"history-collector-{version}.crx"
+        updates_path = args.output_dir / "updates.xml"
+        extension_id_path = args.output_dir / "extension-id.txt"
+        checksums_path = args.output_dir / "checksums.txt"
+        write_deterministic_zip(staging, zip_path)
+        creator.create_crx_file(str(zip_path), str(private_key_path), str(crx_path))
+        result, header = verifier.verify(str(crx_path))
+        if result != verifier.VerifierResult.OK_FULL or header is None or header.crx_id != extension_id:
+            raise ValueError("generated CRX3 failed verification or has the wrong extension ID")
+        write_updates_xml(updates_path, extension_id, version, args.tag)
+        extension_id_path.write_text(extension_id + "\n", encoding="ascii")
+        checksum_paths = [zip_path, crx_path, updates_path, extension_id_path]
+        checksums_path.write_text(
+            "".join(f"{sha256(path)}  {path.name}\n" for path in checksum_paths), encoding="ascii"
+        )
+
+    print(f"Built and verified {args.tag} (extension ID {extension_id})")
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except (OSError, ValueError) as error:
+        raise SystemExit(f"build failed: {error}") from error
diff --git a/scripts/publish_release.py b/scripts/publish_release.py
new file mode 100644
index 0000000..bc1fc12
--- /dev/null
+++ b/scripts/publish_release.py
@@ -0,0 +1,392 @@
+#!/usr/bin/env python3
+"""Publish extension release assets through the Gitea REST API."""
+
+import argparse
+import json
+import os
+import re
+import secrets
+from pathlib import Path
+from urllib.error import HTTPError, URLError
+from urllib.parse import quote, urlencode
+from urllib.request import Request, urlopen
+import xml.etree.ElementTree as ET
+
+
+class ApiError(RuntimeError):
+    pass
+
+
+VERSION_RE = re.compile(r"^(?:0|[1-9][0-9]*)(?:\.(?:0|[1-9][0-9]*)){0,3}$")
+EXPECTED_CRX_CONTENT_TYPE = "application/x-chrome-extension"
+
+
+def _safe_error_detail(error, token):
+    try:
+        detail = error.read().decode("utf-8", errors="replace").strip()
+    except (OSError, UnicodeError):
+        detail = ""
+    if token:
+        detail = detail.replace(token, "[REDACTED]")
+    return detail[:500]
+
+
+def api_call(base_url, token, method, path, payload=None, expected_errors=()):
+    url = base_url.rstrip("/") + path
+    body = None if payload is None else json.dumps(payload).encode("utf-8")
+    headers = {"Authorization": f"token {token}", "Accept": "application/json"}
+    if body is not None:
+        headers["Content-Type"] = "application/json"
+    request = Request(url, data=body, headers=headers, method=method)
+    try:
+        with urlopen(request) as response:
+            response_body = response.read()
+            status = response.status
+    except HTTPError as error:
+        if error.code in expected_errors:
+            return error.code, None
+        detail = _safe_error_detail(error, token)
+        suffix = f": {detail}" if detail else ""
+        reason = str(error.reason).replace(token, "[REDACTED]") if token else str(error.reason)
+        raise ApiError(f"Gitea API {method} {path}: HTTP {error.code} {reason}{suffix}") from None
+    except URLError as error:
+        detail = str(error.reason).replace(token, "[REDACTED]") if token else str(error.reason)
+        raise ApiError(f"Gitea API {method} {path}: {detail}") from None
+    if not response_body:
+        return status, None
+    try:
+        return status, json.loads(response_body)
+    except json.JSONDecodeError as error:
+        raise ApiError(f"Gitea API {method} {path}: invalid JSON response") from error
+
+
+def repository_path(repository):
+    parts = repository.split("/", 1)
+    if len(parts) != 2 or not all(parts):
+        raise ValueError("GITEA_REPOSITORY must be OWNER/REPOSITORY")
+    owner, name = (quote(part, safe="") for part in parts)
+    return f"/repos/{owner}/{name}"
+
+
+def get_or_create_release(base_url, token, repo_path, tag, prerelease):
+    encoded_tag = quote(tag, safe="")
+    status, release = api_call(
+        base_url, token, "GET", f"{repo_path}/releases/tags/{encoded_tag}", expected_errors=(404,)
+    )
+    if status == 404:
+        _, release = api_call(
+            base_url,
+            token,
+            "POST",
+            f"{repo_path}/releases",
+            {
+                "tag_name": tag,
+                "name": tag,
+                "body": "Automated Chrome extension release.",
+                "prerelease": prerelease,
+            },
+        )
+    if not isinstance(release, dict) or not isinstance(release.get("id"), int):
+        raise ApiError(f"Gitea API returned an invalid release for tag {tag}")
+    return release
+
+
+def release_assets(base_url, token, repo_path, release_id):
+    _, assets = api_call(base_url, token, "GET", f"{repo_path}/releases/{release_id}/assets")
+    if not isinstance(assets, list):
+        raise ApiError("Gitea API returned an invalid release asset list")
+    return assets
+
+
+def _asset_path(repo_path, release_id, attachment_id):
+    return f"{repo_path}/releases/{release_id}/assets/{attachment_id}"
+
+
+def _upload_asset(base_url, token, repo_path, release_id, path, asset_name):
+    data = path.read_bytes()
+    # A random boundary is also checked against the file so it cannot terminate the part.
+    while True:
+        boundary = f"----history-collector-{secrets.token_hex(16)}"
+        if boundary.encode("ascii") not in data:
+            break
+    filename = path.name.replace("\\", "_").replace('"', "_").replace("\r", "_").replace("\n", "_")
+    disposition_name = asset_name.replace("\\", "_").replace('"', "_").replace("\r", "_").replace("\n", "_")
+    boundary_bytes = boundary.encode("ascii")
+    body = b"--" + boundary_bytes + b"\r\n"
+    body += f'Content-Disposition: form-data; name="attachment"; filename="{filename}"\r\n'.encode("utf-8")
+    body += b"Content-Type: application/octet-stream\r\n\r\n" + data
+    body += b"\r\n--" + boundary_bytes + b"--\r\n"
+    query = urlencode({"name": disposition_name})
+    url_path = f"{repo_path}/releases/{release_id}/assets?{query}"
+    request = Request(
+        base_url.rstrip("/") + url_path,
+        data=body,
+        headers={
+            "Authorization": f"token {token}",
+            "Accept": "application/json",
+            "Content-Type": f"multipart/form-data; boundary={boundary}",
+        },
+        method="POST",
+    )
+    try:
+        with urlopen(request) as response:
+            response_body = response.read()
+            status = response.status
+    except HTTPError as error:
+        detail = _safe_error_detail(error, token)
+        suffix = f": {detail}" if detail else ""
+        reason = str(error.reason).replace(token, "[REDACTED]") if token else str(error.reason)
+        raise ApiError(f"Gitea API POST {url_path}: HTTP {error.code} {reason}{suffix}") from None
+    except URLError as error:
+        detail = str(error.reason).replace(token, "[REDACTED]") if token else str(error.reason)
+        raise ApiError(f"Gitea API POST {url_path}: {detail}") from None
+    if status < 200 or status >= 300:
+        raise ApiError(f"Gitea API POST {url_path}: HTTP {status}")
+    try:
+        asset = json.loads(response_body)
+    except (json.JSONDecodeError, UnicodeDecodeError) as error:
+        raise ApiError(f"Gitea API POST {url_path}: invalid JSON response") from error
+    if not isinstance(asset, dict) or not isinstance(asset.get("id"), int):
+        raise ApiError(f"Gitea API POST {url_path}: invalid attachment response")
+    return asset
+
+
+def _delete_asset(base_url, token, repo_path, release_id, attachment_id):
+    api_call(base_url, token, "DELETE", _asset_path(repo_path, release_id, attachment_id))
+
+
+def _edit_asset(base_url, token, repo_path, release_id, attachment_id, name):
+    api_call(
+        base_url,
+        token,
+        "PATCH",
+        _asset_path(repo_path, release_id, attachment_id),
+        {"name": name},
+    )
+
+
+def _cleanup_asset(base_url, token, repo_path, release_id, attachment_id):
+    if attachment_id is None:
+        return None
+    try:
+        _delete_asset(base_url, token, repo_path, release_id, attachment_id)
+    except ApiError as error:
+        return str(error)
+    return None
+
+
+def replace_asset(base_url, token, repo_path, release_id, path):
+    existing = next(
+        (
+            asset
+            for asset in release_assets(base_url, token, repo_path, release_id)
+            if asset.get("name") == path.name and isinstance(asset.get("id"), int)
+        ),
+        None,
+    )
+    if existing is None:
+        _upload_asset(base_url, token, repo_path, release_id, path, path.name)
+        return
+
+    old_id = existing["id"]
+    temporary_name = f".{path.name}.upload-{secrets.token_hex(12)}"
+    backup_name = f".{path.name}.backup-{secrets.token_hex(12)}"
+    temporary = _upload_asset(base_url, token, repo_path, release_id, path, temporary_name)
+    temporary_id = temporary["id"]
+    old_renamed = False
+    try:
+        _edit_asset(base_url, token, repo_path, release_id, old_id, backup_name)
+        old_renamed = True
+        try:
+            _edit_asset(base_url, token, repo_path, release_id, temporary_id, path.name)
+        except ApiError as error:
+            restore_error = None
+            try:
+                _edit_asset(base_url, token, repo_path, release_id, old_id, path.name)
+            except ApiError as restore_failure:
+                restore_error = str(restore_failure)
+            cleanup_error = _cleanup_asset(
+                base_url, token, repo_path, release_id, temporary_id
+            )
+            details = [str(error)]
+            if restore_error:
+                details.append(f"could not restore previous asset: {restore_error}")
+            if cleanup_error:
+                details.append(f"could not remove temporary asset: {cleanup_error}")
+            raise ApiError("; ".join(details)) from None
+
+        cleanup_error = _cleanup_asset(base_url, token, repo_path, release_id, old_id)
+        if cleanup_error:
+            raise ApiError(f"asset replaced, but could not remove backup asset: {cleanup_error}")
+    except ApiError:
+        if not old_renamed:
+            cleanup_error = _cleanup_asset(base_url, token, repo_path, release_id, temporary_id)
+            if cleanup_error:
+                raise ApiError(f"asset replacement failed; could not remove temporary asset: {cleanup_error}") from None
+        raise
+
+
+def _chrome_version(value, label):
+    if not isinstance(value, str) or not VERSION_RE.fullmatch(value):
+        raise ApiError(f"{label} must contain 1 to 4 numeric Chrome version components")
+    components = tuple(int(component) for component in value.split("."))
+    if any(component > 65535 for component in components):
+        raise ApiError(f"{label} contains a component greater than 65535")
+    return components + (0,) * (4 - len(components))
+
+
+def should_publish_updates(existing_version, candidate_version):
+    if existing_version is None:
+        return True
+    return _chrome_version(candidate_version, "candidate version") > _chrome_version(
+        existing_version, "existing updates.xml version"
+    )
+
+
+def _updates_version(xml_body):
+    try:
+        root = ET.fromstring(xml_body)
+    except ET.ParseError as error:
+        raise ApiError(f"existing updates.xml is not valid XML: {error}") from error
+    for element in root.iter():
+        if element.tag.rsplit("}", 1)[-1] == "updatecheck" and "version" in element.attrib:
+            version = element.attrib["version"]
+            _chrome_version(version, "existing updates.xml version")
+            return version
+    raise ApiError("existing updates.xml has no updatecheck version")
+
+
+def _public_asset_url(base_url, repo_path, asset):
+    for key in ("browser_download_url", "download_url"):
+        if isinstance(asset.get(key), str) and asset[key]:
+            return asset[key]
+    api_suffix = "/api/v1"
+    if base_url.rstrip("/").endswith(api_suffix):
+        server_url = base_url.rstrip("/")[:-len(api_suffix)]
+        return f"{server_url}{repo_path}/releases/download/updates/{quote(asset['name'], safe='')}"
+    raise ApiError("Gitea did not provide a public download URL for existing updates.xml")
+
+
+def _download_anonymously(url, purpose):
+    request = Request(url, headers={"Accept": "application/xml"}, method="GET")
+    try:
+        with urlopen(request) as response:
+            return response.read()
+    except HTTPError as error:
+        raise ApiError(f"anonymous {purpose} request: HTTP {error.code} {error.reason}") from None
+    except URLError as error:
+        raise ApiError(f"anonymous {purpose} request failed: {error.reason}") from None
+
+
+def existing_updates_version(base_url, token, repo_path, release_id):
+    asset = next(
+        (
+            asset
+            for asset in release_assets(base_url, token, repo_path, release_id)
+            if asset.get("name") == "updates.xml"
+        ),
+        None,
+    )
+    if asset is None:
+        return None
+    return _updates_version(
+        _download_anonymously(_public_asset_url(base_url, repo_path, asset), "existing updates.xml")
+    )
+
+
+def _updates_codebase(xml_path):
+    try:
+        root = ET.parse(xml_path).getroot()
+    except (OSError, ET.ParseError) as error:
+        raise ApiError(f"cannot read generated updates.xml: {error}") from error
+    for element in root.iter():
+        if element.tag.rsplit("}", 1)[-1] == "updatecheck":
+            codebase = element.get("codebase")
+            if codebase:
+                return codebase
+    raise ApiError("generated updates.xml has no codebase URL")
+
+
+def verify_public_crx(updates_path):
+    codebase = _updates_codebase(updates_path)
+    request = Request(codebase, headers={"Accept": "application/octet-stream"}, method="GET")
+    try:
+        with urlopen(request) as response:
+            status = response.status
+            content_type = response.headers.get("Content-Type", "")
+            magic = response.read(4)
+    except HTTPError as error:
+        raise ApiError(
+            f"CRX codebase URL is not anonymously reachable (HTTP {error.code}); "
+            "make the release public and configure its MIME type"
+        ) from None
+    except URLError as error:
+        raise ApiError(
+            f"CRX codebase URL is not anonymously reachable ({error.reason}); "
+            "make the release public and configure its MIME type"
+        ) from None
+    if status != 200:
+        raise ApiError(f"CRX codebase URL returned HTTP {status}; make the release public")
+    if magic != b"Cr24":
+        raise ApiError("CRX codebase URL did not return a CRX3 file (missing Cr24 magic)")
+    if content_type.split(";", 1)[0].strip().lower() != EXPECTED_CRX_CONTENT_TYPE:
+        raise ApiError(
+            "CRX codebase URL returned an invalid Content-Type; configure Gitea "
+            "[repository.mimetype_mapping] or a reverse proxy .crx header as "
+            "application/x-chrome-extension"
+        )
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--tag", required=True)
+    parser.add_argument("--directory", required=True, type=Path)
+    parser.add_argument("--repository", default=os.environ.get("GITEA_REPOSITORY"))
+    parser.add_argument("--api-url", default=os.environ.get("GITEA_API_URL"))
+    args = parser.parse_args()
+    token = os.environ.get("GITEA_TOKEN")
+    server_url = os.environ.get("GITEA_SERVER_URL")
+    api_url = args.api_url or (f"{server_url.rstrip('/')}/api/v1" if server_url else None)
+    if not token:
+        raise ValueError("GITEA_TOKEN is required")
+    if not api_url:
+        raise ValueError("GITEA_API_URL or GITEA_SERVER_URL is required")
+    if not args.repository:
+        raise ValueError("GITEA_REPOSITORY is required")
+    if not args.tag.startswith("v"):
+        raise ValueError("tag must start with v")
+
+    version = args.tag[1:]
+    _chrome_version(version, "tag version")
+    repo_path = repository_path(args.repository)
+    directory = args.directory
+    assets = {
+        "crx": directory / f"history-collector-{version}.crx",
+        "zip": directory / f"history-collector-{version}.zip",
+        "checksums": directory / "checksums.txt",
+        "extension_id": directory / "extension-id.txt",
+        "updates": directory / "updates.xml",
+    }
+    if any(not path.is_file() for path in assets.values()):
+        raise ValueError("build directory is missing one or more release assets")
+
+    release = get_or_create_release(api_url, token, repo_path, args.tag, prerelease=False)
+    for key in ("crx", "zip", "checksums", "extension_id"):
+        replace_asset(api_url, token, repo_path, release["id"], assets[key])
+    # Verify the URL emitted in the new XML only after the versioned CRX is public.
+    verify_public_crx(assets["updates"])
+
+    updates_release = get_or_create_release(api_url, token, repo_path, "updates", prerelease=True)
+    old_version = existing_updates_version(api_url, token, repo_path, updates_release["id"])
+    if should_publish_updates(old_version, version):
+        replace_asset(api_url, token, repo_path, updates_release["id"], assets["updates"])
+        print(f"Published {args.tag} and updates.xml")
+    else:
+        print(f"Published {args.tag}; kept existing updates.xml version {old_version}")
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except (ApiError, OSError, ValueError) as error:
+        raise SystemExit(f"publish failed: {error}") from error
diff --git a/scripts/test_publish_release.py b/scripts/test_publish_release.py
new file mode 100644
index 0000000..6ebfb86
--- /dev/null
+++ b/scripts/test_publish_release.py
@@ -0,0 +1,103 @@
+import re
+import tempfile
+import unittest
+from pathlib import Path
+from unittest.mock import patch
+
+from scripts import publish_release
+
+
+class Response:
+    def __init__(self, body=b'{"id": 1}', status=201, headers=None):
+        self.body = body
+        self.status = status
+        self.headers = headers or {}
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        return False
+
+    def read(self, size=-1):
+        return self.body if size < 0 else self.body[:size]
+
+
+class PublishReleaseTest(unittest.TestCase):
+    def test_upload_is_multipart_with_attachment_field(self):
+        with tempfile.TemporaryDirectory() as temporary:
+            path = Path(temporary) / "package.crx"
+            path.write_bytes(b"Cr24\x03payload")
+            with patch("scripts.publish_release.urlopen", return_value=Response()) as request:
+                publish_release._upload_asset(
+                    "https://gitea.example/api/v1", "secret-token", "/repos/o/r", 4, path, "package.crx"
+                )
+        sent = request.call_args.args[0]
+        body = sent.data
+        content_type = sent.get_header("Content-type")
+        boundary = re.search(r"boundary=([^;]+)", content_type).group(1).encode("ascii")
+        self.assertIn(b'name="attachment"', body)
+        self.assertIn(b"filename=\"package.crx\"", body)
+        self.assertIn(b"Cr24\x03payload", body)
+        self.assertTrue(body.endswith(b"--" + boundary + b"--\r\n"))
+
+    def test_edit_and_delete_use_release_scoped_attachment_path(self):
+        with patch("scripts.publish_release.api_call") as call:
+            publish_release._edit_asset("base", "token", "/repos/o/r", 9, 12, "new.crx")
+            publish_release._delete_asset("base", "token", "/repos/o/r", 9, 12)
+        self.assertEqual(call.call_args_list[0].args[3], "/repos/o/r/releases/9/assets/12")
+        self.assertEqual(call.call_args_list[1].args[3], "/repos/o/r/releases/9/assets/12")
+
+    def test_public_crx_check_is_anonymous_and_allows_content_type_parameters(self):
+        with tempfile.TemporaryDirectory() as temporary:
+            updates = Path(temporary) / "updates.xml"
+            updates.write_text(
+                '<gupdate><app><updatecheck codebase="https://public.example/package.crx" /></app></gupdate>',
+                encoding="utf-8",
+            )
+            with patch(
+                "scripts.publish_release.urlopen",
+                return_value=Response(
+                    b"Cr24\x03payload",
+                    status=200,
+                    headers={"Content-Type": "application/x-chrome-extension; charset=binary"},
+                ),
+            ) as request:
+                publish_release.verify_public_crx(updates)
+        self.assertIsNone(request.call_args.args[0].get_header("Authorization"))
+
+    def test_second_replacement_is_single_asset_and_version_downgrades_are_skipped(self):
+        assets = []
+        next_id = iter(range(1, 10))
+
+        def upload(*args):
+            asset = {"id": next(next_id), "name": args[-1]}
+            assets.append(asset)
+            return asset
+
+        def edit(*args):
+            attachment_id, name = args[-2:]
+            next(asset for asset in assets if asset["id"] == attachment_id)["name"] = name
+
+        def delete(*args):
+            attachment_id = args[-1]
+            assets[:] = [asset for asset in assets if asset["id"] != attachment_id]
+
+        with tempfile.TemporaryDirectory() as temporary:
+            path = Path(temporary) / "package.crx"
+            path.write_bytes(b"data")
+            with patch("scripts.publish_release.release_assets", side_effect=lambda *args: assets.copy()), \
+                 patch("scripts.publish_release._upload_asset", side_effect=upload), \
+                 patch("scripts.publish_release._edit_asset", side_effect=edit), \
+                 patch("scripts.publish_release._delete_asset", side_effect=delete):
+                publish_release.replace_asset("base", "token", "/repos/o/r", 9, path)
+                publish_release.replace_asset("base", "token", "/repos/o/r", 9, path)
+
+        self.assertEqual(assets, [{"id": 2, "name": "package.crx"}])
+        self.assertFalse(publish_release.should_publish_updates("2.4.0", "2.3.9"))
+        self.assertFalse(publish_release.should_publish_updates("2.4.0", "2.4.0"))
+        self.assertTrue(publish_release.should_publish_updates("2.4.0", "2.4.1"))
+
+
+if __name__ == "__main__":
+    unittest.main()