Comment by galkk

This is also standard feature for qmk based keyboards (ergodox, dactyl etc):

https://beta.docs.qmk.fm/using-qmk/advanced-keycodes/feature...

It doesn't require any special support and works in every OS.

Here is how it looks in ZSA visual configuratior, for example: https://configure.ergodox-ez.com/moonlander/layouts/ZrQev/Eo...