Examine source code of Window Fullscreen for YouTube

{
  "manifest_version": 3,
  "name": "Window Fullscreen for YouTube",
  "version": "0.2.6",
  "description": "Watch YouTube in true windowed fullscreen — fill your browser window without going OS-level fullscreen. Free and open source.",
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "action": {
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png"
    },
    "default_popup": "options.html",
    "default_title": "Window Fullscreen for YouTube"
  },
  "permissions": [
    "storage"
  ],
  "host_permissions": [
    "*://www.youtube.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "window-fullscreen-for-youtube@dorzairi.dev",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "data_collection_permissions": {
    "required": [
      "none"
    ]
  }
}