There is no such thing as an unusual keyboard, and the reason you have been able to rename kar files as mid and see the lyrics in the kn screen may be because your kar files either happened to have both formats programmed in the first place or maybe started out as midi files renamed to kar.

I have thousands of kar files. They have lyrics embedded in track 2 as general purpose text meta events, the original specification. The kn reads standard tune 1000 format lyrics which are embedded in track 1 as true lyric meta events, a different format.

Many sequencer programs allow conversion between the two standards for this very reason. Thus it is just incomplete information to say that all kar file lyrics can be displayed in the kn screen just by renaming to mid, since only some will.

This becomes apparent from a wider experience of actual experimentation and the necessary good understanding of theory