Kleinkind am Mac: Keyboard Clean Tool and Little Fingers

Keyboard Cleaner

Black screen helps cleaning it. Bug: cmd tab not shown but works and then cmd q quits the wrong app.
https://jan.prima.de/~jan/plok/archives/48-Keyboard-Cleaner.html

Little Fingers

shift ctrl option cmd L locks everything except the power button.
https://shauninman.com/archive/2017/02/04/little_fingers

Keyboard Clean Tool

Locks only keyboard not mouse.
https://folivora.ai/keyboardcleantool/