For people that type a lot using Level 3 (e.g. using the QWERTZ layout), AltGr on Caps is probably more important. On NixOS, it’s set with two options:
The kernel console REALLY doesn’t like E1 putting the lv5 switch on <M-f>, and instead deletes the f key, so don’t use the second option if your layout does that. (Just try it out and don’t gc until you’ve verified all keys work.)
For people that type a lot using Level 3 (e.g. using the QWERTZ layout), AltGr on Caps is probably more important. On NixOS, it’s set with two options:
The kernel console REALLY doesn’t like E1 putting the lv5 switch on
<M-f>, and instead deletes the f key, so don’t use the second option if your layout does that. (Just try it out and don’t gc until you’ve verified all keys work.)