Examine source code of Shopping List Utility

{
  "manifest_version": 2,
  "name": "Shopping List Utility",
  "version": "1.3",
  "description": "A utility to create and manage your shopping lists.",
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "32": "icons/logo_32.png",
      "64": "icons/logo_64.png",
      "128": "icons/logo_128.png"
    }
  },
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png",
    "128": "icons/logo_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e9a501e5-77e8-4655-9c53-182e9800fb72}"
    }
  }
}