Examine source code of TKRClient

{
  "name": "TKRClient",
  "description": "TKRClient allows you to color pick your name, copy names and reduce spam on iogames.fun",
  "version": "1.2",
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "gvbeguaeraebibgeaiugreukgaegkuae@example.com"
    }
  },
  "browser_action": {
    "default_popup": "active.html",
    "default_icon": "favicon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://iogames.fun/",
        "http://iogames.fun/"
      ],
      "js": [
        "script.js"
      ]
    }
  ]
}