Examine source code of NX Enhanced

{
  "manifest_version": 2,
  "name": "NX Enhanced (Official)",
  "version": "5.1.3",
  "description": "Adds quality-of-life features to NextDNS website for a more practical usability",
  "icons": {
    "128": "icon.png"
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://my.nextdns.io/*",
        "https://api.nextdns.io/*"
      ],
      "js": [
        "utils.js",
        "NXEnhanced.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options-page.html"
  },
  "browser_action": {
    "default_title": "NX Enhanced",
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8dd97833-6035-4627-8ee6-5cc54dd44012}"
    }
  }
}