Examine source code of Google meet joiner

{
  "manifest_version": 2,
  "name": "Google meet joiner",
  "version": "0.3",
  "description": "Mutes audio and video, joins the google meet.",
  "content_scripts": [
    {
      "matches": [
        "*://meet.google.com/*"
      ],
      "js": [
        "joiner.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{cd0b04d2-4d17-4951-bccd-310c4eaab08d}"
    }
  }
}