Examine source code of YouTube Grid Controller

{
  "manifest_version": 3,
  "name": "__MSG_appName__",
  "version": "1.3.2",
  "description": "Настройте отображение списка видео в YouTube",
  "permissions": [
    "storage",
    "scripting"
  ],
  "optional_permissions": [
    "https://www.youtube.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "gridcontroller@example.com"
    }
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "icons": {
    "48": "icon.png"
  },
  "default_locale": "en"
}