Big thx
. I've compared libnickel files and they are really equal, but:
1. different Kobo models have different keyboard layout
2. the offset positions (base addresses) are exactly same in libnickel file for all models (Mark3-Mark6).
Therefore I have to create 3x libnickel and copy (by script) the right one for actual model. It is intended not for me but for all peoples which want to use/download cs(sk) keyboard patch along with the trans_cs(sk).qm file and others.