diff --git a/CONTEXT.md b/CONTEXT.md
index 23c13f3..8c4a3e8 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -36,3 +36,7 @@ _Avoid_: 下载、匯出
 **L1 零泄漏**:
 左栏 IP 列表(扫描层)只显示共识徽章与多源一致国家;任何单源数据(运营商、分数、城市)不进 L1,留在详情层。
 _Avoid_: 列表层泄漏
+
+**通道**:
+同一套插件代码面向特定浏览器(Chrome/Firefox)的发行变体;各有独立的 manifest 派生与「检查更新」比对的 Release 资产前缀。
+_Avoid_: 浏览器版、浏览器分支
diff --git a/docs/adr/0002-firefox-channel-amo-unlisted-derived-manifest.md b/docs/adr/0002-firefox-channel-amo-unlisted-derived-manifest.md
new file mode 100644
index 0000000..1adf831
--- /dev/null
+++ b/docs/adr/0002-firefox-channel-amo-unlisted-derived-manifest.md
@@ -0,0 +1,8 @@
+# Firefox 通道经 AMO unlisted 签名分发,manifest 构建期派生
+
+Chrome 与 Firefox 共用 `extension/` 同一套代码,`public/manifest.json` 是唯一 manifest 事实源(Chrome 版原样);Firefox 版由 `scripts/make-firefox-manifest.mjs` 在构建时派生 `dist/manifest.json`:background 以事件页 `scripts` 取代 `service_worker`(`type: module` 必须保留——background.js 与 index 共享 rollup 代码分块,顶层有 import),并加入 `browser_specific_settings.gecko`(id=`ip-radar-extension@steponeerror.github.io`,strict_min_version=127,即 optional_host_permissions 的支持门槛)。发行走 AMO unlisted 自签名(免费,不公开上架):`web-ext sign` 产物 xpi 直接分发,新版本重复上传签名后,已安装者由 AMO 更新服务自动更新。唯一不可逆点:gecko id 首次签名后即为 AMO 永久身份,换 id 等于发布一个新扩展。
+
+## Considered Options
+
+- 未签名 zip + `about:debugging` 临时加载 — 否决:重启即失,日常自用不可接受。
+- 单 manifest 双写 background(`service_worker`+`scripts` 并存)— 否决:Chrome 侧产生未知键告警,公共 manifest 混入通道细节;派生保 Chrome 版零污染。
diff --git a/extension/.gitignore b/extension/.gitignore
index 3a77e8c..d0d0f6c 100644
--- a/extension/.gitignore
+++ b/extension/.gitignore
@@ -1,3 +1,5 @@
 node_modules/
 dist/
 *.zip
+web-ext-artifacts/
+amo.env
diff --git a/extension/README.md b/extension/README.md
index 0143dd2..5a073dc 100644
--- a/extension/README.md
+++ b/extension/README.md
@@ -19,6 +19,17 @@ npm run build
 
 也可解壓 `ip-radar-extension.zip`，載入解壓後包含 `manifest.json` 的資料夾。
 
+## Firefox
+
+在 `extension` 目錄執行 `npm run build:firefox`：產出 Firefox 版 `dist`（manifest 由 Chrome 版派生，`background` 改為事件頁並加入 `browser_specific_settings`），並打包 `IP.Radar.Firefox_v<版本>.zip`。
+
+- 臨時安裝：Firefox 開啟 `about:debugging#/runtime/this-firefox`，按「Load Temporary Add-on」，選擇 `dist` 內的 `manifest.json`。臨時附加元件重啟 Firefox 後即消失。
+- 永久安裝需 AMO 簽名（免費，unlisted 不會公開上架）：建立 `amo.env`（內含 `WEB_EXT_API_KEY`、`WEB_EXT_API_SECRET`），執行 `set -a; . amo.env; set +a` 後再 `npx web-ext sign --source-dir dist --channel unlisted`，簽好的 XPI 在 `web-ext-artifacts/`。
+- 新版本重複簽名上傳後，已安裝者由 AMO 自動更新。
+- gecko id 為 `ip-radar-extension@steponeerror.github.io`，一經簽名即永久綁定，不可更換。
+- Firefox 通道的「檢查更新」比對 Release 的 `IP.Radar.Firefox_*.zip` 資產。
+- 發佈時需在 GitHub Release 上傳名為 `IP.Radar.Firefox_v<版本>.zip` 的資產，Firefox 端「檢查更新」才會提示就緒；已簽名安裝者由 AMO 自動更新。
+
 ## 功能
 
 - 一批預設最多 100 個 IPv4 / IPv6，可在設定調整單次最大查詢數（1–1,000）；換行、逗號、分號或空格分隔，去重並提示無效項目。
diff --git a/extension/package.json b/extension/package.json
index 0bb8691..24c1641 100644
--- a/extension/package.json
+++ b/extension/package.json
@@ -6,6 +6,7 @@
   "scripts": {
     "dev": "vite --host 127.0.0.1",
     "build": "tsc --noEmit && vite build",
+    "build:firefox": "VITE_CHANNEL=firefox npm run build && node scripts/make-firefox-manifest.mjs && rm -f IP.Radar.Firefox_v$npm_package_version.zip && cd dist && zip -qr ../IP.Radar.Firefox_v$npm_package_version.zip .",
     "test": "vitest run"
   },
   "dependencies": {
diff --git a/extension/public/icons/icon-128.png b/extension/public/icons/icon-128.png
index b20935c..7e7e3ee 100644
Binary files a/extension/public/icons/icon-128.png and b/extension/public/icons/icon-128.png differ
diff --git a/extension/public/icons/icon-32.png b/extension/public/icons/icon-32.png
index ac0f34b..4f8d7aa 100644
Binary files a/extension/public/icons/icon-32.png and b/extension/public/icons/icon-32.png differ
diff --git a/extension/public/icons/icon-64.png b/extension/public/icons/icon-64.png
index aedb829..56d37b9 100644
Binary files a/extension/public/icons/icon-64.png and b/extension/public/icons/icon-64.png differ
diff --git a/extension/scripts/make-firefox-manifest.mjs b/extension/scripts/make-firefox-manifest.mjs
new file mode 100644
index 0000000..7d10308
--- /dev/null
+++ b/extension/scripts/make-firefox-manifest.mjs
@@ -0,0 +1,26 @@
+// Firefox manifest 从 Chrome 版派生:单一事实源 public/manifest.json,不双维护
+import { readFile, writeFile } from "node:fs/promises";
+import { pathToFileURL } from "node:url";
+
+const GECKO_ID = "ip-radar-extension@steponeerror.github.io";
+
+export function firefoxManifest(manifest) {
+  return {
+    ...manifest,
+    // Firefox MV3 用事件页(background.scripts),不支持 service_worker;type:module 必须
+    // 保留:background.js 与 index 共享 rollup 代码分块,顶层有 import
+    background: { scripts: ["background.js"], type: "module" },
+    browser_specific_settings: {
+      gecko: { id: GECKO_ID, strict_min_version: "127.0" }, // 127 = optional_host_permissions
+    },
+  };
+}
+
+if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
+  const manifest = JSON.parse(await readFile("public/manifest.json", "utf8"));
+  await writeFile(
+    "dist/manifest.json",
+    JSON.stringify(firefoxManifest(manifest), null, 2) + "\n",
+  );
+  console.log(`dist/manifest.json → Firefox (gecko id ${GECKO_ID})`);
+}
diff --git a/extension/scripts/make-firefox-manifest.test.mjs b/extension/scripts/make-firefox-manifest.test.mjs
new file mode 100644
index 0000000..04e0ba1
--- /dev/null
+++ b/extension/scripts/make-firefox-manifest.test.mjs
@@ -0,0 +1,19 @@
+import { readFileSync } from "node:fs";
+import { test, expect } from "vitest";
+import { firefoxManifest } from "./make-firefox-manifest.mjs";
+
+test("firefox manifest derives from the chrome manifest", () => {
+  const chrome = JSON.parse(
+    readFileSync(new URL("../public/manifest.json", import.meta.url), "utf8"),
+  );
+  const fx = firefoxManifest(chrome);
+  expect(fx.background).toEqual({ scripts: ["background.js"], type: "module" });
+  expect(fx.browser_specific_settings.gecko).toEqual({
+    id: "ip-radar-extension@steponeerror.github.io",
+    strict_min_version: "127.0",
+  });
+  // 除 background/gecko 外逐字段继承 Chrome manifest:权限/图标/popup 不双维护
+  const { background, browser_specific_settings, ...rest } = fx;
+  const { background: chromeBackground, ...chromeRest } = chrome;
+  expect(rest).toEqual(chromeRest);
+});
diff --git a/extension/src/UpdateCheck.tsx b/extension/src/UpdateCheck.tsx
index 2d4d5e8..582b408 100644
--- a/extension/src/UpdateCheck.tsx
+++ b/extension/src/UpdateCheck.tsx
@@ -10,6 +10,11 @@ const RELEASES_API =
   "https://api.github.com/repos/steponeerror/ip-radar-desktop/releases/latest";
 const RELEASES_URL =
   "https://github.com/steponeerror/ip-radar-desktop/releases/latest";
+// 通道资产前缀:Firefox 构建(VITE_CHANNEL=firefox)比对 Firefox zip,默认 Chrome
+const ASSET_PREFIX =
+  import.meta.env.VITE_CHANNEL === "firefox"
+    ? "IP.Radar.Firefox_"
+    : "IP.Radar.Chrome_";
 export function UpdateCheck() {
   const { t } = useI18n();
   const [busy, setBusy] = useState(false);
@@ -39,7 +44,7 @@ export function UpdateCheck() {
           !Array.isArray(release.assets) ||
           !release.assets.some(
             (asset: { name?: string }) =>
-              asset.name?.startsWith("IP.Radar.Chrome_") && asset.name.endsWith(".zip"),
+              asset.name?.startsWith(ASSET_PREFIX) && asset.name.endsWith(".zip"),
           )
         ) {
           setMessage("新版本的擴充功能下載尚未就緒，請稍後再試。");
diff --git a/extension/src/__tests__/background-firefox.test.ts b/extension/src/__tests__/background-firefox.test.ts
new file mode 100644
index 0000000..493478f
--- /dev/null
+++ b/extension/src/__tests__/background-firefox.test.ts
@@ -0,0 +1,38 @@
+import { it, expect, vi, afterEach } from "vitest";
+afterEach(() => vi.unstubAllGlobals());
+// Firefox 没有 storage.local.setAccessLevel;initialize 必须跳过它并照常完成其余初始化。
+// 独立文件:background 模块的监听注册副作用需要全新的模块注册表。
+it("initialize survives without setAccessLevel (Firefox)", async () => {
+  let onInstalled: Function = () => {};
+  const setPopup = vi.fn();
+  let state: Record<string, unknown> = {};
+  vi.stubGlobal("chrome", {
+    runtime: {
+      id: "test",
+      getURL: (p: string) => `chrome-extension://test/${p}`,
+      onMessage: { addListener: vi.fn() },
+      onInstalled: { addListener: (f: Function) => (onInstalled = f) },
+      onStartup: { addListener: vi.fn() },
+    },
+    storage: {
+      local: {
+        get: async () => state,
+        set: async (v: Record<string, unknown>) => {
+          state = v;
+        },
+        // 故意不提供 setAccessLevel
+      },
+    },
+    alarms: {
+      create: vi.fn(),
+      clear: vi.fn(),
+      onAlarm: { addListener: vi.fn() },
+    },
+    action: { setPopup, onClicked: { addListener: vi.fn() } },
+    tabs: { create: vi.fn() },
+  });
+  await import("../background");
+  onInstalled();
+  await vi.waitFor(() => expect(setPopup).toHaveBeenCalled());
+  expect(setPopup).toHaveBeenCalledWith({ popup: "index.html?mode=popup" });
+});
diff --git a/extension/src/background.ts b/extension/src/background.ts
index 94b1955..4cc52fa 100644
--- a/extension/src/background.ts
+++ b/extension/src/background.ts
@@ -147,9 +147,11 @@ chrome.action.onClicked.addListener(() => {
   });
 });
 async function initialize() {
-  await chrome.storage.local.setAccessLevel({
-    accessLevel: "TRUSTED_CONTEXTS",
-  });
+  // Firefox 没有 setAccessLevel(Chrome 专属);缺省即仅受信上下文可读,跳过不阻塞其余初始化
+  if (chrome.storage.local.setAccessLevel)
+    await chrome.storage.local.setAccessLevel({
+      accessLevel: "TRUSTED_CONTEXTS",
+    });
   const state = await read();
   await chrome.action.setPopup({
     popup: state.settings.openInTab ? "" : "index.html?mode=popup",