[pdntspa]

I dont know about Win11, but in Win10, it is still there. You can see it in MDI apps and, in a few rare circumstances, I have seen the window manager seemingly crash and flash the old Win2000-style boxy design before going back to what it currently does.

[bombcar]

Microsoft is really good at supporting the old libraries and GUIs etc (is the Windows 3.11 font picker still there?) - the problem is that modern programs aren't built to the W2K paradigm so even if you force W11 to "look" like windows 2000 all the apps will not suddenly grow title bars, etc.