They are control key sequences that are arranged so that a typist need never remover their fingers from the keyboard. The control key was to the left of the A so easily pressed with you left little finger.

You had full control of the cursor without the need for dedicated arrow keys or page up and down keys. It worked on a normal terminal keyboard. I first used it on an Apple ][ with a Z80 add-on that ran CP/M.

Thanks for sharing! I'd consider all those things true for Emacs/Vim bindings as well? (Just curious if you'd disagree with that assessment.)