My difficulty with this argument is that an owner of the copy of the GPL
library has a wide right to make a derivative work on the owner's computer
by virtue of the GPL and/or a more limited right in the U.S. by virtue of
section 117 of the U.S. Copyright Act.In the scenario we were talking about, the addition is released publicly *as* an addition. If it were just made and used privately, you might be right--in any case, that would be a different question.
