Examine source code of Hahu oldness

{
  "manifest_version": 3,
  "name": "Hahu oldness",
  "version": "0.1",
  "description": "Enhances the UX of hasznaltauto.hu vehicle selling site by displaying the days passed since the ad creation",
  "content_scripts": [
    {
      "matches": [
        "*://www.hasznaltauto.hu/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{5162f4f7-0c93-4e95-aa7b-af6b51ddce34}",
      "strict_min_version": "58.0"
    }
  }
}