Examine source code of Tenhou UI translator

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "9.4.3",
  "default_locale": "en",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "16": "icons/tenhou-16.png",
    "19": "icons/tenhou-19.png",
    "32": "icons/tenhou-32.png",
    "38": "icons/tenhou-38.png",
    "64": "icons/tenhou-64.png",
    "128": "icons/tenhou-128.png"
  },
  "page_action": {
    "default_icon": {
      "16": "icons/tenhou-16.png",
      "19": "icons/tenhou-19.png",
      "32": "icons/tenhou-32.png",
      "38": "icons/tenhou-38.png",
      "64": "icons/tenhou-64.png",
      "128": "icons/tenhou-128.png"
    },
    "default_popup": "options.html",
    "default_title": "__MSG_popupTitle__"
  },
  "permissions": [
    "storage",
    "tabs",
    "activeTab",
    "webRequest",
    "webRequestBlocking",
    "*://tenhou.net/*",
    "*://ron2.jp/*",
    "*://cdn.tenhou.net/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://ron2.jp/3*",
        "*://tenhou.net/3*",
        "*://tenhou.net/4*",
        "*://tenhou.net/5*",
        "*://tenhou.net/sc/*",
        "*://tenhou.net/ranking.html",
        "*://tenhou.net/stat/*"
      ],
      "js": [
        "translations.js",
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_end"
    }
  ],
  "options_ui": {
    "chrome_style": true,
    "page": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f6d2b88f-7911-47b4-8a12-af6c380784cc}"
    }
  }
}