"name": "Polymer Airlines", "start_url": "/", "display": "standalone", "icons": [{ "src": "icons/icon-192.png", "sizes": "192x192", "type": "image/png", "density": "4.0" }], "orientation": "portrait", "gcm_sender_id": "129757602160" } JSON Manifest With Manifests Metadata delegated to one file Extensible & crawlable