Examine source code of Dark Mode Extension

{
  "manifest_version": 2,
  "name": "Dark Mode Extension",
  "version": "1.0",
  "description": "Enable dark mode for websites",
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "darkmode.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a949f055-f62e-4564-84a3-92e26b2c76da}"
    }
  }
}