feedback5: Japanese, Korean and Traditional Chinese ship — the official game texts of the JP / KR / TW clients (data/i18n/ja.json 96.5 %, ko.json 97.4 %, zh-TW.json 91.1 % of 22 114 texts, built with build-i18n --lang from ArknightsAssets/ArknightsGamedata) and minimal UI packs public/i18n/ja.json, ko.json, zh-TW.json (a _meta manifest, no UI strings yet): ja / ko fall back to the English UI, zh-TW to the Simplified Chinese UI (no fallback; numbers in 萬 / 億); the owner's decision of 2026-10-07; UI translations welcome from the community; golden: unchanged (client text only)

- The packs: _meta = type lang, the code, its own and English name (日本語 / Japanese, 한국어 / Korean, 繁體中文 /
  Traditional Chinese), version 0.2.0, app >=0.2.0, authors, credits (the official client data, © Hypergryph (/ Yostar
  for JP and KR), via ArknightsAssets/ArknightsGamedata), fallback ["en"] for ja / ko and [] for zh-TW; formatted as
  `node tools/i18n.mjs template` writes them, so a translator runs it on the shipped file and keeps the manifest.
- Built offline from the tables W5AD downloaded and checked today (jp / kr 51.10.0, tw 51.2.0; copied into
  .cache/gamedata-<code>): coverage as W5AD measured; `build-i18n --lang <code> --check` up to date for en, ja, ko,
  zh-TW. `node tools/i18n.mjs check --all --strict`: 0 errors (en complete; ja / ko / zh-TW 0 of 1022 msgids, fallback).
  `node tools/packs.mjs list` lists the four packs with their game texts; `tools/package.mjs --dry-run --list` ships
  data/i18n and public/i18n of all four and the generated packs/index.json.
- With five languages the menu is a list (ui/lang.js SEGMENTED_MAX 4, W5AD's rule): test/ui/i18n.e2e.test.js reads and
  picks either form, expects the shipped languages, and checks each new pack in the browser (its official game text,
  the fallback UI, <html lang>) — SP_E2E=1: 3 / 3; the title page of the five devices (devices.e2e "title page") still
  fits: 5 / 5.
- Docs: docs/I18N.md (intro, §2, §5 "Shipped packs" with the call for UI translations), docs/PLAYING.md (语言),
  DESIGN §25.20 and the §25 intro's decisions of 2026-10-07.

Gate: non-browser suites 5024 / 5024 (test/i18n*, test/package, client-static 358 / 358), npm run golden ok,
test/golden.test.js 9 / 9, lint 0 errors, check:imports ok, typecheck ok.

test/ui/i18n.e2e.test.js

@@ -7,7 +7,10 @@
 // game-data overlay (data/i18n/en.json) is applied; `?lang=zh` switches back and leaves the address bar. Language packs
 // (docs/I18N.md "Adding a language", docs/PACKS.md): a pack file dropped into public/i18n/ and a pack folder dropped
 // into packs/ while the server runs show in the menu and switch, with English filling what they lack; a removed pack
-// sends a stored choice back to Chinese. No console / page / request errors. docs/I18N.md.
+// sends a stored choice back to Chinese. The shipped Japanese, Korean and Traditional Chinese packs (the owner's decision of
+// 2026-10-07) switch to their official game texts with the UI of their fallback (English; Simplified Chinese for zh-TW).
+// With more than four languages the menu is a list (ui/lang.js SEGMENTED_MAX): the helpers read and pick either form.
+// No console / page / request errors. docs/I18N.md.
 
 import { test, describe, before, after } from 'node:test';
 import assert from 'node:assert/strict';
@@ -38,6 +41,17 @@ describe('language switch on the title screen', { skip: !ENABLED && 'set SP_E2E=
   after(async () => { removePacks(); await browser?.close(); await srv?.close(); });
 
   const text = (page, sel) => page.$eval(sel, (el) => el.textContent.replace(/\s+/g, ' ').trim());
+  /** The menu's languages, [code, label] — its buttons, or the options of its list. */
+  const menu = (page) => page.$$eval('[data-testid="lang-toggle"] button, [data-testid="lang-toggle"] option',
+    (els) => els.map((e) => [e.dataset.lang ?? e.value, e.textContent.trim()]));
+  /** Pick a language: its button, or its option in the list. */
+  const pick = async (page, code) => {
+    if (await page.$('[data-testid="lang-toggle"] select')) await page.select('[data-testid="lang-toggle"] select', code);
+    else await page.click(`[data-testid="lang-toggle"] button[data-lang="${code}"]`);
+  };
+  const SHIPPED = [['zh', '中文'], ['en', 'English'], ['ja', '日本語'], ['ko', '한국어'], ['zh-TW', '繁體中文']];
+  /** A game text of a shipped pack's overlay (data/i18n/<code>.json; a leaf is a string or { _s }). */
+  const gameText = (code) => { const v = JSON.parse(fs.readFileSync(path.join(ROOT, `data/i18n/${code}.json`), 'utf8')).files.config.modes.mode_multi_abyss.name; return typeof v === 'string' ? v : v._s; };
 
   test('中文 by default; English in place, kept across a reload; ?lang=zh back to Chinese', async () => {
     const page = await browser.newPage();
@@ -52,7 +66,8 @@ describe('language switch on the title screen', { skip: !ENABLED && 'set SP_E2E=
     assert.equal(await text(page, '.title-login .btn--primary'), '开始');
     assert.equal(await page.evaluate(() => document.documentElement.lang), 'zh-CN');
 
-    await page.click('[data-testid="lang-toggle"] button[data-lang="en"]');
+    assert.deepEqual(await menu(page), SHIPPED, 'the shipped languages');
+    await pick(page, 'en');
     await page.waitForFunction(() => document.querySelector('.title-cn')?.textContent.includes('Stronghold Protocol'), { timeout: 8000 });
     assert.equal(await text(page, '.title-cn'), 'Stronghold Protocol: Alliance');
     assert.equal(await text(page, '.title-login .btn--primary'), 'Start');
@@ -93,11 +108,10 @@ describe('language switch on the title screen', { skip: !ENABLED && 'set SP_E2E=
       fs.writeFileSync(path.join(PACK_DIR, 'ui.json'), JSON.stringify({ 开始: 'Qab-Start' }));
       await sleep(1100); // the server's registry looks at the folders again after a second
       await page.goto(`${base}/?lang=zh`, { waitUntil: 'networkidle0' });
-      await page.waitForSelector('.title-screen [data-testid="lang-toggle"] button[data-lang="qaa"]');
-      assert.deepEqual(await page.$$eval('[data-testid="lang-toggle"] button', (bs) => bs.map((b) => [b.dataset.lang, b.textContent.trim()])),
-        [['zh', '中文'], ['en', 'English'], ['qaa', 'Testisch'], ['qab', 'Qabisch']]);
+      await page.waitForFunction(() => [...document.querySelectorAll('.title-screen [data-testid="lang-toggle"] :is(button, option)')].some((e) => (e.dataset.lang ?? e.value) === 'qaa'), { timeout: 8000 });
+      assert.deepEqual(await menu(page), [...SHIPPED.slice(0, 4), ['qaa', 'Testisch'], ['qab', 'Qabisch'], SHIPPED[4]]);
 
-      await page.click('[data-testid="lang-toggle"] button[data-lang="qaa"]');
+      await pick(page, 'qaa');
       await page.waitForFunction(() => document.querySelector('.title-login .btn--primary')?.textContent.includes('Los'), { timeout: 8000 });
       assert.equal(await text(page, '.title-cn'), 'Testprotokoll: Bund', 'an alphabetic title: the display face, an ASCII colon');
       assert.match(await text(page, '.title-tag'), /^Allocate Funds and Operators/, 'untranslated: English, the pack\'s fallback');
@@ -107,22 +121,41 @@ describe('language switch on the title screen', { skip: !ENABLED && 'set SP_E2E=
       await page.waitForFunction(() => globalThis.__SP__?.data?.locale() === 'qaa', { timeout: 8000 });
       assert.equal(await page.evaluate(() => globalThis.__SP__.data.get('config').modes.mode_multi_abyss.name), 'Ultimate Simulation');
 
-      await page.click('[data-testid="lang-toggle"] button[data-lang="qab"]');
+      await pick(page, 'qab');
       await page.waitForFunction(() => document.querySelector('.title-login .btn--primary')?.textContent.includes('Qab-Start'), { timeout: 8000 });
       assert.equal(await text(page, '.title-cn'), '卫戍协议：盟约', 'no fallback declared: the Chinese msgid');
 
-      await page.click('[data-testid="lang-toggle"] button[data-lang="qaa"]');
+      await pick(page, 'qaa');
       await page.waitForFunction(() => document.querySelector('.title-login .btn--primary')?.textContent.includes('Los'), { timeout: 8000 });
       removePacks();
       await sleep(1100);
       await page.reload({ waitUntil: 'networkidle0' });
       await page.waitForSelector('.title-screen .title-cn');
       assert.equal(await text(page, '.title-cn'), '卫戍协议：盟约', 'the stored pack is gone: Chinese');
-      assert.deepEqual(await page.$$eval('[data-testid="lang-toggle"] button', (bs) => bs.map((b) => b.dataset.lang)), ['zh', 'en']);
+      assert.deepEqual(await menu(page), SHIPPED);
       assert.deepEqual(problems, []);
     } finally {
       removePacks();
       await page.close();
     }
   });
+  test('the shipped 日本語 / 한국어 / 繁體中文 packs: the official game texts, the UI of their fallback (English; Simplified Chinese for zh-TW)', async () => {
+    const page = await browser.newPage();
+    await page.setViewport({ width: 1600, height: 900 });
+    const problems = [];
+    page.on('console', (m) => { if (m.type() === 'error') problems.push(`console: ${m.text()}`); });
+    page.on('pageerror', (e) => problems.push(`pageerror: ${e.message}`));
+    page.on('response', (r) => { if (r.status() >= 400 && !/fonts\.(googleapis|gstatic)/.test(r.url())) problems.push(`http ${r.status()}: ${r.url()}`); });
+    await page.goto(`${base}/?lang=zh`, { waitUntil: 'networkidle0' });
+    await page.waitForSelector('.title-screen [data-testid="lang-toggle"]');
+    for (const [code, ui, htmlLang] of [['ja', 'Start', 'ja'], ['ko', 'Start', 'ko'], ['zh-TW', '开始', 'zh-TW']]) {
+      await pick(page, code);
+      await page.waitForFunction((c) => globalThis.__SP__?.data?.locale() === c, { timeout: 8000 }, code);
+      assert.equal(await page.evaluate(() => globalThis.__SP__.data.get('config').modes.mode_multi_abyss.name), gameText(code), `${code}: the official game text`);
+      assert.equal(await text(page, '.title-login .btn--primary'), ui, `${code}: the fallback UI`);
+      assert.equal(await page.evaluate(() => document.documentElement.lang), htmlLang);
+    }
+    assert.deepEqual(problems, []);
+    await page.close();
+  });
 });