Examine source code of Google Meet DJ

{
  "manifest_version": 2,
  "name": "Google Meet DJ",
  "version": "1.0.0",
  "description": "Volume control for Google Meet.",
  "browser_specific_settings": {
    "gecko": {
      "id": "google-meet-dj@qt-kaneko.github.io"
    }
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://meet.google.com/*"
      ],
      "js": [
        "./content-scripts/volume-control.js"
      ],
      "run_at": "document_end"
    }
  ],
  "page_action": {
    "browser_style": true,
    "default_icon": "./popup/icon.png",
    "hide_matches": [
      "*://meet.google.com/",
      "*://meet.google.com/?*",
      "*://meet.google.com/_meet/whoops",
      "*://meet.google.com/_meet/whoops?*"
    ],
    "show_matches": [
      "*://meet.google.com/*"
    ],
    "default_title": "Google Meet DJ",
    "default_popup": "./popup/index.html"
  }
}