Trying to make 9front work on QWERTZ

Ahoy,

I've been trying to give 9front a test ride for a while now, and I'm
stuck with one specific problem.

So I have a German keyboard layout where <, > and | are on the same
key. However, while I have no problems with these keys, in 9front the
key seems to be dead on all of my keyboards. I tried quite a lot of
them, both inside QEMU on two different computers and on a dedicated
ThinkPad. Also, using the de layout does not fix that.

Is that a known problem or a configuration error?