I find the "CODE" key to be a bit weird to have on a
computer keyboard. On typewriters it was a modifier that changed layer, to one that contained both commands and alternate characters.
On computers, its role is split up between Control, Windows/Command, Alt/Option/Alt Gr.
It started being included in custom key sets as part of sets that mimicked typewriters' specifically.
I'd think that the closest equivalent to a computer keyboard would actually be the Fn key, because that one is used to change layer.
If I were to choose textual legends, I think I would instead prioritise having two "COM" modifiers. That abbreviated legend could be interpreted as either "Command" or "
Compose". Mac users want two Command keys, and some Unix and Windows users want one Compose key. (I have seen max one Compose key on a keyboard). Compose keys are often in place of a Menu key, and they have the same scancode in the USB HID standard.
Some sets use the word "Super" or "Meta" instead of "Windows". Meta (◆) stems from the '70s and is traditional on many Unix keyboards. It used to be used the same way as a command key. Sun/ORACLE still sells keyboards with Meta and Compose keys for use with Solaris and Linux.
"Super" is used by some desktop environments on Unix/Linux. Some vintage keyboards had both Super and Meta, and combinations of them.