CountryType offers countries based on Intl::getRegionBundle()->getCountryNames() which may not be ISO 3166-1 compliant. The Country constraint can check for a ISO 3166-1 complaint country.

As an example, for "en" regions, "Ascension Island" is offered as a country, but is disallowed by the constraint. We can, of course, fix this by compiling and providing our own list.

As a better approach, can CountryType have an option to show only countries which match the Country constraint?