Examine source code of TubeScroll

{
  "name": "TubeScroll",
  "short_name": "TubeScroll",
  "version": "1.2.0",
  "description": "A Chrome extension to enable scrolling in fullscreen mode on YouTube.",
  "manifest_version": 3,
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "action": {
    "default_icon": "icons/icon-16.png",
    "default_popup": "index.html",
    "default_title": "TubeScroll"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "christopherdboss@gmail.com"
    }
  }
}