chromium/chrome/test/data/web_apps/file_handler.json

{
  "name": "Web app with file handlers",
  "start_url": "file_handler_index.html",
  "display": "standalone",
  "icons": [
    {
      "src": "basic-48.png",
      "sizes": "48x48",
      "type": "image/png"
    },
    {
      "src": "basic-192.png",
      "sizes": "192x192",
      "type": "image/png"
    }
  ],
  "file_handlers": [
    {
      "action": "file_handler_action.html",
      "name": "Plain Text",
      "accept": {
        "text/plain": [".txt"]
      }
    }
  ]
}