chromium/extensions/test/data/manifest_tests/web_app_shortcut_icons_valid.json

{
  "name": "test extension",
  "manifest_version": 2,
  "version": "1.0.0.0",
  "app": {
    "launch": {
      "web_url": "https://chromium.org/"
    }
  },
  "web_app_shortcut_icons": {
    "0": {
      "64": "shortcut_icons/0/64.png",
      "640": "shortcut_icons/0/640.png"
    }
  }
}