Examine source code of Site Language Switcher

{
  "manifest_version": 2,
  "name": "Site Language Switcher",
  "version": "1.0",
  "description": "为不同网站设置不同的 Accept-Language",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "storage",
    "<all_urls>",
    "requestHeaders"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon-48.svg"
    }
  },
  "icons": {
    "48": "icons/icon-48.svg"
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d4e8e626-7083-4d78-aad4-f5a1bc27642b}"
    }
  }
}