NK3 HMAC Slot 1/2: which one to use?

Hi everybody,

using the Nitrokey App 2, I can only create one HMAC slot: HmacSlot2.

However, using nitropy, there is a second slot which I can write to. Well actually, its the first one: HmacSlot1.

The official docs mention NK3 supports only one HMAC secret too.

Is HmacSlot1 used internally? KeePassXC finds and supports both slots. I can think of some usecases to have to slots configured but I feel like I should ask first.

Thanks!