Examine source code of Simple Proxy Toggle

{
  "manifest_version": 2,
  "name": "ProxyToggle",
  "version": "0.1",
  "description": "A convenient toolbar button to toggle top-level proxy settings.",
  "icons": {
    "48": "img/socks.svg"
  },
  "permissions": [
    "proxy"
  ],
  "background": {
    "scripts": [
      "src/pt-background.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "img/socks.svg",
    "default_title": "ProxyToggle",
    "default_popup": "src/pt-popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "proxytoggle@example.com"
    }
  }
}