[montroser]

So interesting to see how the ADM-3A keyboard layout itself was such a fundamental influence for ESC and hjkl movement in vi.

[kps]

And that I suspect originates with ASCII Control-H = backspace (cursor left), Control-J = line feed (cursor down). Control-K and Control-L don't match but weren't so important that they couldn't be repurposed by an early display terminal.

[sudahtigabulan]

Yep. It's all in the manual.

https://archive.org/details/ADM-3A-User-Reference-Manual-Apr...

(This page, and Figure 1-3 below).