Examine source code of EV Info

{
  "manifest_version": 3,
  "name": "EV Info",
  "version": "1.0",
  "description": "Provides calculated data for electric cars on the 'hasznaltauto.hu' page.",
  "icons": {
    "24": "icons/icon-24.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png",
    "256": "icons/icon-256.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "szabolcs.lelesz@gmail.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.hasznaltauto.hu/*"
      ],
      "js": [
        "evinfo.js"
      ]
    }
  ]
}