What do function keys F13-F24 do on Manjaro (KDE)?

I just found out today that are actual not 12 but 24 functions keys! These can be accessed by holding Shift and F1-F12 where the Shift acts as an increase the current number on the function key by 12, e.g. SHIFT+F1=F13.
Now do these do anything specific or they are just extra keys, one can assign things to? I tried to find something on the Internet but I didn’t find anything beyond what happens on Windows but also not in a great extent.

that’s just shift+f1 it does not = f13 the f keys are single keys or fn+# depending on your keyboard.

So F13 would be Fn+1+3? And what does that do?

yes the F keys exist up to 24, but I’ve never seen F13-F24 on any keyboard. I can produce them with my programmable keyboard, probably yours can do that too. This sends the appropriates keycodes directly from the hardware. I’