1. I have one of the oldest living IBM Series M keyboards with the original IBM APL2 keycaps.
  2. I use APL a lot.
  3. The APL support in /usr/share/X11/xkb/ doesn't include support for that keyboard.

So I patched /usr/share/X11/xkb/symbols/apl and /usr/share/X11/xkb/rules/evdev.extras.xml to provide that support.  If anyone is interested, I'll be glad to provide the patches.  (They're against Fedora 33.)

Chris Moller