Examine source code of Tiny Game

{
  "manifest_version": 2,
  "name": "Tiny Game",
  "version": "1.0",
  "description": "Play a relaxing Snake mini-game directly from your browser popup.",
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "128": "icon128.png"
    }
  },
  "icons": {
    "128": "icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{cf77d82d-4fb0-4baf-86f3-fdc03ee793a7}"
    }
  }
}