Examine source code of Switch UA PLUS

{
  "manifest_version": 2,
  "name": "Switch UA PRO",
  "version": "1.0.1",
  "description": "Take control of your browsing by easily changing your User-Agent with what you want. Selection mode available: Manual, Auto, Random",
  "author": "Matt Glow",
  "homepage_url": "https://github.com/h3xstone/switchUAPro",
  "icons": {
    "32": "icons/logo32.png",
    "48": "icons/logo48.png",
    "96": "icons/logo96.png",
    "128": "icons/logo128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup/index.html",
    "default_title": "UA Switcher Pro",
    "default_icon": {
      "32": "icons/logo32.png",
      "48": "icons/logo48.png",
      "96": "icons/logo96.png",
      "128": "icons/logo128.png"
    }
  },
  "permissions": [
    "storage",
    "alarms",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "web_accessible_resources": [
    "inject.js",
    "storage.js",
    "storage2.js"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "storage.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{516084ad-633a-4563-9a7b-eb6b398bca20}"
    }
  }
}