Examine source code of SIMTEST.IT Mobile internet proxy

{
  "description": "SIMTEST.it Mobile proxy is one of the features of SIMTEST.it service that enables you to browse 3G and 4G mobile networks in more than 70 countries worldwide.",
  "manifest_version": 2,
  "name": "SIMTEST.IT Mobile proxy",
  "author": "Web team",
  "version": "5.1.4",
  "homepage_url": "https://simtest.it",
  "icons": {
    "48": "icons/icon.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "webNavigation",
    "proxy",
    "activeTab",
    "tabs",
    "storage",
    "notifications",
    "unlimitedStorage",
    "<all_urls>"
  ],
  "browser_action": {
    "default_title": "SIMTEST.IT Mobile proxy",
    "default_popup": "ui/popup/index.html",
    "default_icon": {
      "48": "icons/icon-inactive.png"
    }
  },
  "background": {
    "persistent": true,
    "scripts": [
      "lib/utility.js",
      "lib/core-polyfill.js",
      "lib/api-manager.js",
      "ui/js/jquery.min.js",
      "scripts/proxy/chrome-proxy.js",
      "scripts/background/proxy-handler.js"
    ]
  },
  "options_ui": {
    "page": "ui/settings.html",
    "open_in_tab": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "scripts/content/content-script.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "91.1.0",
      "id": "proxy@simtest.it"
    }
  }
}