Examine source code of Swap — Currency Converter

{
  "manifest_version": 3,
  "name": "Swap — Currency Converter",
  "version": "1.0.0",
  "description": "Quick currency conversion in your toolbar. ECB reference rates, no API key, works offline with the last fetched rates.",
  "author": "InternetMango Solutions LLP",
  "browser_specific_settings": {
    "gecko": {
      "id": "currency-swap@internetmango.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "permissions": [
    "storage"
  ],
  "action": {
    "default_popup": "popup.html",
    "default_title": "Currency converter",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  }
}