Examine source code of UCLN Calculator

{
  "manifest_version": 2,
  "name": "UCLN Calculator",
  "version": "1.0",
  "description": "Calculate the Greatest Common Divisor (GCD) of two integers.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{2befdb59-73de-4509-a187-043ef9995a55}"
    }
  }
}