Examine source code of Universal Theme Toggle

{
  "manifest_version": 3,
  "name": "Universal Theme Toggle",
  "version": "1.0",
  "description": "Toggle dark/light mode on any site.",
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_title": "Toggle theme"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "darkmodetoggle@kharedeveloper.com",
      "strict_min_version": "109.0"
    }
  }
}