Examine source code of Setinrate Price Spinner

{
  "manifest_version": 3,
  "name": "Setinrate Price Spinner",
  "version": "1.0",
  "description": "افزودن دکمه‌های ▲ ▼ کنار فیلد قیمت (fee) در سایت setinrate.com",
  "content_scripts": [
    {
      "matches": [
        "*://setinrate.com/room*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "pricespinner@example.com"
    }
  }
}