Examine source code of Dark Mode Reader

{
  "manifest_version": 3,
  "name": "Dark Mode Reader",
  "description": "A dark mode for reading websites",
  "version": "1.0.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "{072d84d6-6fcc-46bc-a71e-4063e66a3e28}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "action": {
    "default_title": "Toggle Dark Mode"
  },
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  }
}