Examine source code of ProxySwitch SS

{
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "shellshot525@gmail.com"
    }
  },
  "name": "ProxySwitch",
  "description": "This extension disable/enable proxy with one click.",
  "version": "1.1resigned1",
  "browser_action": {
    "default_icon": "toggle-on-48.png"
  },
  "background": {
    "scripts": [
      "popup.js"
    ]
  },
  "permissions": [
    "proxy",
    "storage"
  ],
  "icons": {
    "128": "ProxySwitch-128.png"
  }
}