You didn't understand the parenthetical, busybox has no relation to the Windows shell.

It is a Windows shell. A POSIX Windows shell.

Such as should have been present at the beginning, not the OS/2 affliction.

"shell" in Windows roughly refers to the GUI, not a CLI host like it does in Unix.

Unfortunately it is still clear you don't understand my comment nor the linked wikipedia page at all. Windows Shell isn't the same use of the word you are overloading here in this thread and you are out in left field from what everyone else is talking about. Maybe revisit the wikipedia page and read a little more, look at the project descriptions&screencaps, and it will make sense to you.

Indeed the first thing I do on a new Windows install is load Open Shell.

You still can, and it's even exposed specifically for making constrained setups (though not everyone knows to use it)

Busybox has a great shell in the Windows port.

It calls itself "bash" but it is really the Almquist shell with a bit of added bash syntactic sugar. It does not support arrays.

https://frippery.org/busybox/index.html