diff --git a/eslint.config.mjs b/eslint.config.mjs
index da21dc6..5f2f9f5 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -8,6 +8,7 @@ export default [
       sourceType: "module",
       globals: {
         chrome: "readonly",
+        browser: "readonly",
         window: "readonly",
         document: "readonly",
         navigator: "readonly",
diff --git a/extension/locales/de.json b/extension/locales/de.json
index 42c1b11..6703db2 100644
--- a/extension/locales/de.json
+++ b/extension/locales/de.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Equalizer",
   "AUDIO_COMING_SOON": "Demnächst",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Einführung neu starten",
+  "BTN_RESTART_TOUR_TOOLTIP": "Startet die Einführung für neue Benutzer erneut",
+  "HINT_SELECT_VIDEO": "Wähle hier dein Video aus!"
 }
diff --git a/extension/locales/es.json b/extension/locales/es.json
index 97b4495..98415e2 100644
--- a/extension/locales/es.json
+++ b/extension/locales/es.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Ecualizador",
   "AUDIO_COMING_SOON": "Próximamente",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Reiniciar tutorial",
+  "BTN_RESTART_TOUR_TOOLTIP": "Reiniciar el tutorial de inicio",
+  "HINT_SELECT_VIDEO": "¡Selecciona tu video aquí!"
 }
diff --git a/extension/locales/fr.json b/extension/locales/fr.json
index 83ad29c..e5e7122 100644
--- a/extension/locales/fr.json
+++ b/extension/locales/fr.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Égaliseur",
   "AUDIO_COMING_SOON": "Bientôt disponible",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Redémarrer le tutoriel",
+  "BTN_RESTART_TOUR_TOOLTIP": "Recommencer le tutoriel d'intégration",
+  "HINT_SELECT_VIDEO": "Sélectionnez votre vidéo ici !"
 }
diff --git a/extension/locales/it.json b/extension/locales/it.json
index c1af1cc..002fdee 100644
--- a/extension/locales/it.json
+++ b/extension/locales/it.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Equalizzatore",
   "AUDIO_COMING_SOON": "Prossimamente",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Riavvia tutorial",
+  "BTN_RESTART_TOUR_TOOLTIP": "Riavvia il tutorial iniziale",
+  "HINT_SELECT_VIDEO": "Seleziona il tuo video qui!"
 }
diff --git a/extension/locales/ja.json b/extension/locales/ja.json
index bbcff90..7237ef8 100644
--- a/extension/locales/ja.json
+++ b/extension/locales/ja.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "イコライザー",
   "AUDIO_COMING_SOON": "近日公開",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "チュートリアルを再起動",
+  "BTN_RESTART_TOUR_TOOLTIP": "オンボーディングチュートリアルを再起動する",
+  "HINT_SELECT_VIDEO": "ここで動画を選択してください！"
 }
diff --git a/extension/locales/ko.json b/extension/locales/ko.json
index fe61d49..d0c6f11 100644
--- a/extension/locales/ko.json
+++ b/extension/locales/ko.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "이퀄라이저",
   "AUDIO_COMING_SOON": "출시 예정",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "튜토리얼 다시 시작",
+  "BTN_RESTART_TOUR_TOOLTIP": "온보딩 튜토리얼을 다시 시작합니다",
+  "HINT_SELECT_VIDEO": "여기에서 비디오를 선택하세요!"
 }
diff --git a/extension/locales/nl.json b/extension/locales/nl.json
index 7ea5786..37d18e0 100644
--- a/extension/locales/nl.json
+++ b/extension/locales/nl.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Equalizer",
   "AUDIO_COMING_SOON": "Binnenkort beschikbaar",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Tutorial opnieuw starten",
+  "BTN_RESTART_TOUR_TOOLTIP": "Start de introductie-tutorial opnieuw",
+  "HINT_SELECT_VIDEO": "Selecteer hier je video!"
 }
diff --git a/extension/locales/pl.json b/extension/locales/pl.json
index 24f0eb2..fa7d561 100644
--- a/extension/locales/pl.json
+++ b/extension/locales/pl.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Korektor",
   "AUDIO_COMING_SOON": "Wkrótce",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Uruchom samouczek ponownie",
+  "BTN_RESTART_TOUR_TOOLTIP": "Uruchom ponownie samouczek powitalny",
+  "HINT_SELECT_VIDEO": "Wybierz swoje wideo tutaj!"
 }
diff --git a/extension/locales/pt-BR.json b/extension/locales/pt-BR.json
index f15f2d6..aa417c1 100644
--- a/extension/locales/pt-BR.json
+++ b/extension/locales/pt-BR.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Equalizador",
   "AUDIO_COMING_SOON": "Em breve",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Reiniciar tutorial",
+  "BTN_RESTART_TOUR_TOOLTIP": "Reiniciar o tutorial de introdução",
+  "HINT_SELECT_VIDEO": "Selecione seu vídeo aqui!"
 }
diff --git a/extension/locales/pt.json b/extension/locales/pt.json
index 8250a52..f761222 100644
--- a/extension/locales/pt.json
+++ b/extension/locales/pt.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Equalizador",
   "AUDIO_COMING_SOON": "Em breve",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Reiniciar tutorial",
+  "BTN_RESTART_TOUR_TOOLTIP": "Reiniciar o tutorial de introdução",
+  "HINT_SELECT_VIDEO": "Selecione o seu vídeo aqui!"
 }
diff --git a/extension/locales/ru.json b/extension/locales/ru.json
index b7ed9f2..c7429d7 100644
--- a/extension/locales/ru.json
+++ b/extension/locales/ru.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Эквалайзер",
   "AUDIO_COMING_SOON": "Скоро",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Перезапустить обучение",
+  "BTN_RESTART_TOUR_TOOLTIP": "Запустить приветственное руководство заново",
+  "HINT_SELECT_VIDEO": "Выберите ваше видео здесь!"
 }
diff --git a/extension/locales/tr.json b/extension/locales/tr.json
index 0529502..855e35a 100644
--- a/extension/locales/tr.json
+++ b/extension/locales/tr.json
@@ -206,7 +206,7 @@
   "AUDIO_PARAM_RELEASE": "Release",
   "AUDIO_EQUALIZER": "Ekolayzer",
   "AUDIO_COMING_SOON": "Çok yakında",
-  "BTN_RESTART_TOUR": "",
-  "BTN_RESTART_TOUR_TOOLTIP": "",
-  "HINT_SELECT_VIDEO": ""
+  "BTN_RESTART_TOUR": "Eğitimi Yeniden Başlat",
+  "BTN_RESTART_TOUR_TOOLTIP": "Tanıtım eğitimini yeniden başlat",
+  "HINT_SELECT_VIDEO": "Videonuzu buradan seçin!"
 }
diff --git a/scripts/build-extension.js b/scripts/build-extension.js
index 3709925..ffcb971 100644
--- a/scripts/build-extension.js
+++ b/scripts/build-extension.js
@@ -106,7 +106,7 @@ function copyExtensionFiles(targetDir, browserName) {
         const uStart = '// --- UNINSTALL_URL_INJECT_START ---';
         const uEnd = '// --- UNINSTALL_URL_INJECT_END ---';
         const uPattern = new RegExp(`${uStart}[\\s\\S]+?${uEnd}`);
-        const placeholderUrl = "https://example.com/uninstall-placeholder"; // TODO: Replace me
+        const placeholderUrl = "https://bye.koalastuff.net/c/camp_99ztjRVbK1BNN2RU";
         
         let uRep = `${uStart}\n        // This block is automatically updated by /scripts/build-extension.js\n`;
         uRep += `        const UNINSTALL_URL = "${placeholderUrl}";\n`;
diff --git a/scripts/test-locales.js b/scripts/test-locales.js
index 81bac1a..d6df537 100644
--- a/scripts/test-locales.js
+++ b/scripts/test-locales.js
@@ -48,7 +48,7 @@ try {
 const enDict = JSON.parse(fs.readFileSync(enPath, 'utf8'));
 const enKeys = Object.keys(enDict);
 
-const localeFiles = fs.readdirSync(localesDir).filter(file => file.endsWith('.json') && file !== 'en.json');
+const localeFiles = fs.readdirSync(localesDir).filter(file => file.endsWith('.json'));
 
 console.log(`Auditing i18n locales using ${enKeys.length} baseline keys from en.json...\n`);
 
@@ -79,8 +79,21 @@ for (const file of localeFiles) {
 
     const missingKeys = enKeys.filter(k => !keys.includes(k));
     const extraKeys = keys.filter(k => !enKeys.includes(k));
+    const emptyKeys = keys.filter(k => typeof dict[k] === 'string' && dict[k].trim() === '');
+    const placeholderKeys = keys.filter(k => {
+      if (typeof dict[k] !== 'string') return false;
+      const val = dict[k];
+      const lower = val.toLowerCase();
+      return (
+        lower.includes('placeholder') ||
+        lower.includes('todo:') ||
+        lower.includes('tbd:') ||
+        /\bTODO\b/.test(val) ||
+        /\bTBD\b/.test(val)
+      );
+    });
 
-    if (missingKeys.length > 0 || extraKeys.length > 0) {
+    if (missingKeys.length > 0 || extraKeys.length > 0 || emptyKeys.length > 0 || placeholderKeys.length > 0) {
       hasError = true;
       console.error(`❌ ${file} has inconsistencies:`);
       if (missingKeys.length > 0) {
@@ -89,6 +102,12 @@ for (const file of localeFiles) {
       if (extraKeys.length > 0) {
         console.error(`  Extra keys (${extraKeys.length}):`, extraKeys);
       }
+      if (emptyKeys.length > 0) {
+        console.error(`  Empty translation values (${emptyKeys.length}):`, emptyKeys);
+      }
+      if (placeholderKeys.length > 0) {
+        console.error(`  Placeholder/TODO values (${placeholderKeys.length}):`, placeholderKeys);
+      }
     } else {
       console.log(`✓ ${file} is fully consistent (matches all keys).`);
     }
diff --git a/scripts/test-website-locales.mjs b/scripts/test-website-locales.mjs
index b4bd9b3..02d0e42 100644
--- a/scripts/test-website-locales.mjs
+++ b/scripts/test-website-locales.mjs
@@ -17,7 +17,7 @@ const enDict = JSON.parse(fs.readFileSync(enPath, 'utf8'));
 const enKeys = Object.keys(enDict).sort();
 
 const localeFiles = fs.readdirSync(localesDir)
-  .filter(file => file.endsWith('.json') && file !== 'en.json')
+  .filter(file => file.endsWith('.json'))
   .sort();
 
 let hasError = false;
@@ -51,8 +51,24 @@ for (const file of localeFiles) {
 
     const missingKeys = enKeys.filter(k => !keys.includes(k));
     const extraKeys = keys.filter(k => !enKeys.includes(k));
+    const emptyKeys = keys.filter(k => {
+      if (file === 'en.json' && k === 'CANONICAL_PATH') return false;
+      return typeof dict[k] === 'string' && dict[k].trim() === '';
+    });
+    const placeholderKeys = keys.filter(k => {
+      if (typeof dict[k] !== 'string') return false;
+      const val = dict[k];
+      const lower = val.toLowerCase();
+      return (
+        lower.includes('placeholder') ||
+        lower.includes('todo:') ||
+        lower.includes('tbd:') ||
+        /\bTODO\b/.test(val) ||
+        /\bTBD\b/.test(val)
+      );
+    });
 
-    if (missingKeys.length > 0 || extraKeys.length > 0) {
+    if (missingKeys.length > 0 || extraKeys.length > 0 || emptyKeys.length > 0 || placeholderKeys.length > 0) {
       hasError = true;
       console.error(`❌ ${file} has inconsistencies:`);
       if (missingKeys.length > 0) {
@@ -61,6 +77,12 @@ for (const file of localeFiles) {
       if (extraKeys.length > 0) {
         console.error(`  Extra keys (${extraKeys.length}):`, extraKeys);
       }
+      if (emptyKeys.length > 0) {
+        console.error(`  Empty translation values (${emptyKeys.length}):`, emptyKeys);
+      }
+      if (placeholderKeys.length > 0) {
+        console.error(`  Placeholder/TODO values (${placeholderKeys.length}):`, placeholderKeys);
+      }
     } else {
       console.log(`✓ ${file} is fully consistent (matches all keys).`);
     }
diff --git a/website/locales/it.json b/website/locales/it.json
index e901b70..7191af3 100644
--- a/website/locales/it.json
+++ b/website/locales/it.json
@@ -2,7 +2,7 @@
   "LANG_CODE": "it",
   "HTML_CLASS": "lang-it",
   "CANONICAL_PATH": "it/",
-  "LANG_TOGGLE_URL": "",
+  "LANG_TOGGLE_URL": "../",
   "LANG_TOGGLE_TEXT": "EN",
   "OG_LOCALE": "it_IT",
   "META_TITLE": "KoalaSync | Sincronizza Netflix, YouTube e qualsiasi video con gli amici",
diff --git a/website/locales/ja.json b/website/locales/ja.json
index 49eb8ed..eae29e3 100644
--- a/website/locales/ja.json
+++ b/website/locales/ja.json
@@ -2,7 +2,7 @@
   "LANG_CODE": "ja",
   "HTML_CLASS": "lang-ja",
   "CANONICAL_PATH": "ja/",
-  "LANG_TOGGLE_URL": "",
+  "LANG_TOGGLE_URL": "../",
   "LANG_TOGGLE_TEXT": "EN",
   "OG_LOCALE": "ja_JP",
   "META_TITLE": "KoalaSync | Netflix、YouTube、あらゆる動画を友達と同期視聴",
diff --git a/website/locales/ko.json b/website/locales/ko.json
index 39fb942..3ae5173 100644
--- a/website/locales/ko.json
+++ b/website/locales/ko.json
@@ -2,7 +2,7 @@
   "LANG_CODE": "ko",
   "HTML_CLASS": "lang-ko",
   "CANONICAL_PATH": "ko/",
-  "LANG_TOGGLE_URL": "",
+  "LANG_TOGGLE_URL": "../",
   "LANG_TOGGLE_TEXT": "EN",
   "OG_LOCALE": "ko_KR",
   "META_TITLE": "KoalaSync | Netflix, YouTube 및 모든 비디오를 친구와 실시간 동기화 시청",
diff --git a/website/locales/nl.json b/website/locales/nl.json
index d141c55..c07f65a 100644
--- a/website/locales/nl.json
+++ b/website/locales/nl.json
@@ -2,7 +2,7 @@
   "LANG_CODE": "nl",
   "HTML_CLASS": "lang-nl",
   "CANONICAL_PATH": "nl/",
-  "LANG_TOGGLE_URL": "",
+  "LANG_TOGGLE_URL": "../",
   "LANG_TOGGLE_TEXT": "EN",
   "OG_LOCALE": "nl_NL",
   "META_TITLE": "KoalaSync | Synchroniseer Netflix, YouTube & elke video met vrienden",
diff --git a/website/locales/pl.json b/website/locales/pl.json
index a216060..479e7fc 100644
--- a/website/locales/pl.json
+++ b/website/locales/pl.json
@@ -2,7 +2,7 @@
   "LANG_CODE": "pl",
   "HTML_CLASS": "lang-pl",
   "CANONICAL_PATH": "pl/",
-  "LANG_TOGGLE_URL": "",
+  "LANG_TOGGLE_URL": "../",
   "LANG_TOGGLE_TEXT": "EN",
   "OG_LOCALE": "pl_PL",
   "META_TITLE": "KoalaSync | Synchronizuj Netflix, YouTube i dowolne wideo ze znajomymi",
diff --git a/website/locales/pt.json b/website/locales/pt.json
index 19a3365..4a4889b 100644
--- a/website/locales/pt.json
+++ b/website/locales/pt.json
@@ -2,7 +2,7 @@
   "LANG_CODE": "pt",
   "HTML_CLASS": "lang-pt",
   "CANONICAL_PATH": "pt/",
-  "LANG_TOGGLE_URL": "",
+  "LANG_TOGGLE_URL": "../",
   "LANG_TOGGLE_TEXT": "EN",
   "OG_LOCALE": "pt_PT",
   "META_TITLE": "KoalaSync | Sincronize Netflix, YouTube e qualquer vídeo com os amigos",
diff --git a/website/locales/tr.json b/website/locales/tr.json
index bbf5bbd..1758864 100644
--- a/website/locales/tr.json
+++ b/website/locales/tr.json
@@ -2,7 +2,7 @@
   "LANG_CODE": "tr",
   "HTML_CLASS": "lang-tr",
   "CANONICAL_PATH": "tr/",
-  "LANG_TOGGLE_URL": "",
+  "LANG_TOGGLE_URL": "../",
   "LANG_TOGGLE_TEXT": "EN",
   "OG_LOCALE": "tr_TR",
   "META_TITLE": "KoalaSync | Netflix, YouTube ve Herhangi Bir Videoyu Arkadaşlarınızla Eşitleyin",