That's just how to add a keyboard... in Z80 code. Indeed a private (coder's) joke, that won't help you much, but I must say I laughed
Gloriou, try to give more information on your need, and MSX brand/model to have more serious answers
MSX2 AX370, MSX2 AX350 - Adding external keyboard, as my right arrow is damaged in the AX370 and it also a better solution to save our own keyboards from damaging.
Yesterday, I connected my external keyboard (IBM Fast Response) to my mobile using ps2 to USB connector and USB to Type C. It worked fine on fMSX on Honor mobile