Examine source code of Youtube UI

{
  "manifest_version": 3,
  "name": "Youtube UI",
  "version": "1.0.0",
  "description": "Customize YouTube layout and appearance by disabling Big Mode and changing the number of items per row.",
  "action": {
    "default_popup": "index.html"
  },
  "permissions": [
    "storage",
    "scripting",
    "tabs"
  ],
  "host_permissions": [
    "https://www.youtube.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "32": "logo32.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "youtube-ui@mgahelrasoul.com",
      "strict_min_version": "109.0"
    }
  }
}