Examine source code of StealthSurf VPN

{
  "manifest_version": 2,
  "name": "StealthSurf VPN",
  "short_name": "StealthSurf",
  "version": "1.0.14",
  "description": "Браузерное расширение для пользователей сервиса. Подключайтесь к своим конфигам прямо из браузера — без лишних настроек.",
  "author": "StealthSurf VPN",
  "homepage_url": "https://stealthsurf.net",
  "developer": {
    "name": "StealthSurf VPN",
    "url": "https://stealthsurf.net"
  },
  "permissions": [
    "proxy",
    "storage",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>",
    "alarms",
    "management"
  ],
  "browser_action": {
    "default_popup": "src/assets/popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "background": {
    "page": "background.html",
    "persistent": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@stealthsurf.app",
      "strict_min_version": "91.1.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "113.0"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "web_accessible_resources": [
    "callback.html"
  ]
}