> you are using a super set of letters (or am I reaching too far)
You're not though. The original letters are not available, so uppercase is not a superset of lowercase. (Unless you're just stating your opinion that the set of uppercase letters happens to be super)
I always get confused around this and it seems to depend on specific keyboard and software. It seems to mostly be Alt, sometimes Alt Gr, and sometimes the Windows key. But I do remember using Meta to mean Alt when I was setting things up in Ubuntu maybe ten years ago.
I think Super and Meta are the vendor independent terms.
Ctrl - Ctrl - Ctrl
Super - Windows - Command
Left/Right Super - ?? - Open/Close Apple
Left Meta - Alt - Option
Right Meta - Alt Gr - Right Option?
Anybody able to fill the gaps?
Approaching an Apple keyboard for the first time, I naively thought Command would be Ctrl and was quite confused, since there also is Ctrl. But once you start a terminal it became quite clear that this was not the case. This is quite neat, it directly solves the SIGINT,SIGSTOP / Copy, Ctrl-D? confusion. Also having these operation as OS command means that all programs support them.