Examine source code of VPN Duo - Secure Proxy & VPN

{
  "name": "VPN Duo - Secure Proxy & Privacy VPN",
  "version": "1.0.0",
  "description": "Secure proxy & dual-server VPN extension. Protect your browsing, prevent WebRTC IP leaks, and enjoy fast location switching.",
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "vpn-duo-official@vpn-duo.com",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "incognito": "spanning",
  "permissions": [
    "proxy",
    "storage",
    "webRequest",
    "webRequestBlocking",
    "activeTab",
    "tabs",
    "scripting",
    "privacy"
  ],
  "host_permissions": [
    "https://web.vpn-duo.com/*",
    "https://stripe.vpn-duo.com/*",
    "https://pro.ip-api.com/*",
    "https://api.ipify.org/*"
  ],
  "background": {
    "scripts": [
      "config.js",
      "decrypt.js",
      "common.js",
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "VPN Duo - Secure Proxy & Privacy VPN",
    "default_icon": {
      "16": "assets/icon-16.png",
      "32": "assets/icon-32.png",
      "48": "assets/icon-48.png",
      "128": "assets/icon-128.png"
    }
  },
  "icons": {
    "16": "assets/icon-16.png",
    "32": "assets/icon-32.png",
    "48": "assets/icon-48.png",
    "128": "assets/icon-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://web.vpn-duo.com/*"
      ],
      "js": [
        "content-script.js"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "callback.html"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}