Not that I know of.
I can't find anything either, now that I actually look. The best I can find is a very brief summary at the top of [[Wikipedia:GFDL compliance]].
I even emailed the FSF for clarification and got back that simplifications are oversimplifications and people really do need to read the license.
That's just what I was saying - you can't have an official simplification, since it would end up conflicting with the actual license.
My goodness the GFDL is a crap license for a wiki ...
Too late to do anything about that now, though...