Countries codes returned by system.getCountry() ?

Does someone know exactly which/how many country codes will be returned? I know it will return codes from the ISO 3166-2 norm… But every single ones, or a subset only?

I need an accurate list if possible.

Not so sure actually

// returns the 2 digit ISO 3166-1-alpha-2 format country code this client is running in (as looked up via an IP-to-location database)
// e.g "US" or "UK".
virtual const char *GetIPCountry() = 0;

Looks like it can return any of those (for now).