Examine source code of Avito notifier

{
  "manifest_version": 2,
  "name": "Avito notifier",
  "version": "1.0",
  "description": "Уведомления о новых сообщениях на Avito",
  "permissions": [
    "https://www.avito.ru/*",
    "notifications"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.avito.ru/*"
      ],
      "js": [
        "content-script.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d4f637bc-6bca-40ed-aaee-f4643d53e795}"
    }
  }
}