Alt text:
Twitter post by Daniel Feldman (@d_feldman): Linux is the only major operating system to support diagonal mode (credit [Twitter] @xssfox). Image shows an untrawide monitor rotated about 45 degrees, with a horizontal IDE window taking up a bottom triangle. A web browser and settings menu above it are organized creating a window shape almost like a stepped pyramid.
Edit: alt text
How many minor operating systems support it? ๐ค
I'm assuming most that can run Xorg.
Correct
There's ReactOS and BSD off the top of my head.
Haiku counts
I think ToaruOS does? I remember reading something about it but haven't managed to install it yet to verify.
Edit: found it