In change set 5051u62, the implementation of 
ClassDescription>>classComment: was changed from:

   classComment: aString
       ^ self classComment: aString stamp: '<historical>'

to

   classComment: aString
         aString isEmptyOrNil
            ifFalse: [self error: 'class comment set without stamp'].
        ^ self classComment: '' stamp: 'ignored'

This change effectively breaks Squeak from being able to file in 
VisualWorks 3.0 chunk format fileins.  I have found the interoperability 
for fileins between VW and Squeak to be very useful.  In fact, my Squeak 
GLORP port just uses the VW GLORP filein directly.  But, this change 
broke that ability.

So, what was the rationale for making that change in Squeak?  Is there 
any chance we can get it set back to what it was?

Nevin