Examine source code of Youtube Speed Controller

{
  "manifest_version": 3,
  "name": "YouTube Speed Controls",
  "version": "1.0.3",
  "description": "Adds playback speed controls and shortcuts to YouTube videos.",
  "host_permissions": [
    "https://www.youtube.com/*",
    "https://m.youtube.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*",
        "https://m.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "style.css"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "icons/favicon-16x16.png",
    "32": "icons/favicon-32x32.png",
    "48": "icons/favicon.ico"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "absarlearns@gmail.com"
    }
  }
}