Examine source code of Snake port

{
  "manifest_version": 3,
  "name": "Snake",
  "short_name": "Snake",
  "version": "2.2.33",
  "description": "The authentic snake game in a popup.",
  "icons": {
    "16": "images/head.png",
    "48": "images/head.png",
    "128": "images/head.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "action": {
    "default_icon": {
      "16": "images/head.png",
      "24": "images/head.png",
      "32": "images/head.png",
      "48": "images/head.png",
      "128": "images/head.png"
    },
    "default_popup": "index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "snake@yourdomain.com",
      "strict_min_version": "109.0"
    }
  }
}