Examine source code of IntoDNS Checker

{
  "manifest_version": 2,
  "name": "IntoDNS Checker",
  "version": "1.0",
  "description": "IntoDNS checks the health and configuration and provides DNS report and mail servers report.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{30fbb1c7-27a2-4424-b6d8-871f41e8674f}"
    }
  }
}