plan9port VS qtcurve

Acme has a handful of keybindings, like the usual ^A, ^E for navigation, ^Z for undo, etc. Plugging in new ones is a few lines of code, for example my ^S for Putall (saving all windows):

https://github.com/dexen/plan9port/commit/78324a4666c4b5e0bd...

Most of keybindings you might want to add are handled by Acme's "commands" - like Edit. If you repeat them any often, it's easy and straightforward to connect the keybinding to the command in code. Alternatively, to avoid going into C, write a shell script with ready-made command; Acme is well prepared to be managed through shell scripts. The shell scripts have full access to Acme's Windows (open files, directories, scratchpads etc), including ability to edit content, open new ones, interpret right-clicks in new ways, etc.

Not OP, but what about something like https://en.wikipedia.org/wiki/Metisse ?

( https://www.youtube.com/watch?v=Dt3q7Z7RjIU 4min54sec)

Which begat https://dl.acm.org/doi/10.1145/1166253.1166301 from the same institution. ( https://www.youtube.com/watch?v=kUUtiOWTzz4 7min20sec)

Married with something like https://arcan-fe.com/about/

With some https://en.wikipedia.org/wiki/Zooming_user_interface sprinkled in,

not necessarily in the 'style' of https://eaglemode.sourceforge.net/ but the concept.

Rounded with something like https://en.wikipedia.org/wiki/OpenQwaq , or https://en.wikipedia.org/wiki/Open_Cobalt

OFC fully themable like GTK before they broke it, or something like https://github.com/KDE/qtcurve which is endlessly modifiable.

Nirvana!

Well, there's the legendary QtCurve. Don't know why it is not longer included in the default KDE install, or if it even can be used in KDE5, though.