Comment It's been out there for a while (Score 2) 224
It doesn't seem to be widely known, but the MS-DOS 6.0 source code was leaked at some point. However, if you look it up you will only see posts from late 2006 when it was indexed by google code search. There doesn't seem to be any information on how or when it was originally leaked it seems like for whatever reason it wasn't big news at the time.