Examine source code of Wishlist cart icon

{
  "manifest_version": 2,
  "name": "Wishlist cart icon",
  "version": "1.0",
  "description": "The wishlist cart icon is a combination of the shopping cart icon and the heart icon, representing the action of adding items to the cart that the user especially likes or has previously liked.",
  "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": "{0933c86d-f7bd-4d0a-936f-509951b0b2b7}"
    }
  }
}