Examine source code of Proxy Switcher

{
  "manifest_version": 2,
  "name": "Proxy Switcher",
  "version": "1.4",
  "description": "One-click proxy switcher.(No Proxy / System Proxy)",
  "icons": {
    "512": "icon-off.png"
  },
  "permissions": [
    "proxy",
    "privacy"
  ],
  "incognito": "spanning",
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "91.1.0",
      "id": "{f01beb25-b346-46d8-ab51-694a7a836f6d}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": {
      "512": "icon-off.png"
    },
    "default_title": "Proxy Switcher"
  }
}