chrome/test/data/web_apps/install_element/manifest.json

{
  "name": "Web app install element test app with id",
  "id": "some_id",
  "icons": [
    {
      "src": "launcher-icon-1x.png",
      "sizes": "48x48",
      "type": "image/png"
    },
    {
      "src": "launcher-icon-3x.png",
      "sizes": "144x144",
      "type": "image/png"
    }
  ],
  "start_url": "index.html",
  "display": "standalone"
}