GPLv3 and anonymous changes

[Florian Weimer]

I'm glad to see that one of the most-violated clauses of the GPLv2 is
gone, namely:

    a) You must cause the modified files to carry prominent notices
    stating that you changed the files and the date of any change.

Great, thanks.  But one ambiguity in version 2 still remains: are
anonymous changes allowed, or must the authors and copyright holders
be identified?