chromium/chrome/test/data/banners/manifest_maskable.json

{
  "name": "Manifest test app",
  "icons": [
    {
      "src": "launcher-icon-4x.png",
      "sizes": "192x192",
      "type": "image/png",
      "purpose": "any"
    },
    {
      "src": "launcher-icon-3x.png",
      "sizes": "144x144",
      "type": "image/png",
      "purpose": "maskable"
    }
  ],
  "start_url": "manifest_test_page.html",
  "display": "standalone",
  "orientation": "landscape"
}