bb4win, or blackbox 4 windows, or bblean, or bbzero, or xoblite, or whatever
It is one of the many windows shell replacements, that used to be pretty common back in the 2000s from what I've noticed; those times used to have a bunch of futuristic and v cool designs, but I'm getting ahead of myself. Originally a window manager for X11 (that I prefer over w*yl*nd, and C over Rust), ported for windows and modded or forked several times ;w; I'll try to list some forks that I've seen
The one I got is from bb4win/bblean, I got the 64-bit version and extracted it to c:/bblean64. The 32-bit one caused me quite a bit of confusion,,, it is usable, but most of the Windows built-in things you'd open will be the 32-bit version. I know, confusing ;w;
After that, I exit explorer and run it from command line, I'll replace this text with some more detailed steps, such as what to do after you install bblean, how to replace the shell (explorer) with it, and how to configure the menu (maybe)
Then there's maybe a few things to setup
(And here will be some links to the wiki and other things)