Examine source code of Dark Mode Toggle Kittkat

{
  "manifest_version": 3,
  "name": "Dark Mode Toggle",
  "version": "1.0",
  "description": "Toggle dark mode on webpages.",
  "permissions": [
    "activeTab",
    "storage",
    "scripting"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon48.png",
      "128": "icon128.png"
    },
    "icons": {
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "dark-mode-toggle-nbt@gmail.com",
      "strict_min_version": "78.0"
    }
  }
}