Comment by FarmerPotato

In 1991, I used Inside Macintosh for inspiration, but a much broader view of interface was distilled in the MITRE Corporation user interface book.

MITRE successfully conveyed how to have keyboard-operated GUI with plenty of power user modes --all with discoverability. You might call it "fallbacks for every mode".

Its principles combined TUI (then known as CUI) and GUI as well as DSL (domain specific language).

A fully architected program having a DSL (domain specific language) had a console much like a macro recorder: as you used the menus and icons, the console would show the commands you could otherwise type in to get the same effect.

You could edit the console line and re-execute it.

In the 1990s, DSL was a buzzword but if you got it right, your GUI was a power tool.