Examine source code of Custom Currency Converter

{
  "manifest_version": 2,
  "name": "Custom Currency Converter",
  "version": "1.1",
  "description": "A simple and customizable pop-up currency converter.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "https://v6.exchangerate-api.com/",
    "storage"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'; style-src 'self' https://fonts.googleapis.com; font-src 'self' https://fonts.gstatic.com;",
  "browser_specific_settings": {
    "gecko": {
      "id": "{47f075a8-7c64-4f89-9ec4-402d1029efbb}"
    }
  }
}