Examine source code of AntiTestportal

{
  "name": "AntiTestportal",
  "version": "1.2.1",
  "manifest_version": 2,
  "content_scripts": [
    {
      "matches": [
        "*://*.teams.microsoft.com/*",
        "*://*.testportal.net/*",
        "*://*.testportal.pl/*"
      ],
      "js": [
        "index.js"
      ],
      "all_frames": true
    }
  ],
  "web_accessible_resources": [
    "modules/timer.js",
    "modules/focus.js",
    "modules/search.js"
  ],
  "browser_action": {
    "default_title": "AntiTestportal",
    "default_popup": "popup/index.html"
  },
  "permissions": [
    "storage"
  ],
  "icons": {
    "300": "assets/testportal-300.png"
  },
  "background": {
    "scripts": [
      "events/installed.js"
    ]
  }
}