[Symbiote]

It should be fairly trivial.

From the issue as described, the value "visa" worked, but "visadankort" didn't. Denmark's earlier, national debit card system is called DanKort. Nowadays, almost all DanKort cards are issued through Visa, so they are "Visa DanKort" -- within Denmark, there's the option to bypass some sort of fee for a lower cost of processing.

Presumably the value "visadankort" is there to distinguish these cards. However, they can be processed exactly as normal Visa cards.

This is not unique to Denmark, there are a list of card prefixes like this (see 4571 for DanKort[1]), but perhaps the different processing fees in unusual.

[1] https://www.stevemorse.org/ssn/List_of_Bank_Identification_N...