Ctrl-X, Ctrl-C and Ctrl-V isn’t even part of the IBM CUA specification. CUA places the Cut command at Shift-Del, Copy on Ctrl-Insert, and Paste on Shift-Insert.
cmd-K for Cut? I don't ever remember that on the Mac.
I remember the lower left row on the US keyboard was always the first four operations from the nearly-ubiquitous Edit menu since day one.
Z - Undo
X - Cut
C - Copy
V - Paste
Certainly not the flagship apps from Apple. Can you remember an app that did this specifically? I seem to remember even early apps from Microsoft were fairly respectful of the early Mac HIG
Early apps frequently also had "Clear" in the Edit menu, which was like Cut except the cleared item didn't go into the system Clipboard
