Examine source code of Tracking icon

{
  "manifest_version": 2,
  "name": "Tracking icon",
  "version": "1.0",
  "description": "Follow Icon Used to indicate the action of following someone, subscribing to updates from other users, news sites, content, products, etc.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Click me!"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e78f75b9-2ab3-4959-9459-f0ed366bef6b}"
    }
  }
}