Examine source code of YouTube Speed Ctrl

{
  "name": "YouTube Speed Ctrl",
  "version": "1.1",
  "manifest_version": 3,
  "description": "Control YouTube video playback speed with keyboard shortcuts.",
  "browser_specific_settings": {
    "gecko": {
      "id": "youtube-speed-ctrl@yourname.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "action": {
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "commands": {
    "toggle-display": {
      "suggested_key": {
        "default": "Ctrl+Shift+S"
      },
      "description": "Toggle speed display"
    }
  }
}