Examine source code of toggle-useragent

{
  "manifest_version": 2,
  "name": "toggle-useragent",
  "description": "修改指定网址的user-agent,清除此网址缓存",
  "version": "1.0",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "storage",
    "tabs",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "toggle-useragent@jone"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    }
  ],
  "browser_action": {}
}