This endpoint serves two purposes:

1. When called without a countryCode, it returns a list of all supported countries with their codes and full names
2. When called with a specific countryCode, it returns the required address fields and format for that country

This information is used to dynamically build address collection forms with the appropriate fields for each country.

{
  "countries": {
    "US": "United States of America",
    "CA": "Canada",
    "GB": "United Kingdom",
    "DE": "Germany"
  }
}