I remember this popped up on one of the other forums where I am a member. It was my understanding that it is actually some kind of linux derivative written for the 68K Mac hardware and is meant to look and act like the original System/Finder. Someone posted that M6KDE meant Mac, 68k, KDE, with a heavily customized implementation of KDE used to simulate the psuedo-Mac GUI.

I have no idea if any of the above is true, as far as I could tell it was all speculation.