Examine source code of Host Switcher

{
  "manifest_version": 2,
  "name": "Host Switcher",
  "version": "1.0",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icon.png"
  },
  "icons": {
    "32": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{94b22029-880e-4be9-ad5b-ae99b38106dd}"
    }
  }
}