Examine source code of Address book icon

{
  "manifest_version": 2,
  "name": "Address book icon",
  "version": "1.0",
  "description": "The address book icon is commonly understood as an icon representing an email address book or a contact with an email address, combining an image of an address book.",
  "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": "{fde48aa3-d6e6-4130-a0c4-cf61447ecd93}"
    }
  }
}