How to ctrl+\ on a German keyboard (maximize window on 2nd display)

Hello world,

I can't find the key mapping for ctrl+\ (e.g. maximize window on second/third monitor) on my German keyboard.

I've read, that this particular (and important!) mapping isn't listed in the key mapping table to edit, but that the shortcut exists. So, how can you do that on a German layout?

(Pr. 22.1.2, english version)

Thanks in advance! 🙂