Examine source code of Youtube Custom Speed

{
  "manifest_version": 3,
  "name": "__MSG_extName__",
  "description": "__MSG_extDescription__",
  "version": "1.10",
  "default_locale": "en",
  "icons": {
    "128": "icons/icon128.png"
  },
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "options/options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "content/content.js"
      ],
      "run_at": "document_end"
    },
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "content/changespeed.js",
        "content/kbshort.js",
        "content/menu.js",
        "content/observer.js",
        "content/configure.js"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "ui.html",
        "ui-modern.html"
      ],
      "matches": [
        "*://www.youtube.com/*"
      ]
    }
  ],
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "youtube-custom-speed@niziolek.dev"
    }
  }
}