The Duesseldorf court of appeal has opined that the licensing of software under GPL does not grant a trademark license. Here is more information in German. I will post when I see a translation. Thanks to Till Jaeger for posting this to the FSF Legal list. This seems like a completely expected result, but the distinguishing of trademark and copyright licensing under open source licenses is a matter regarding which the courts have not yet caught up with the rules that most attorneys assume to apply: that trademarks and logos included in open source software cannot be used unless that use is consistent with trademark law.
There is an inherent tension between open source licensing and trademark law — open source licenses grants broad rights to modify software, but trademark law limits one’s ability to market modified software under the trademark of the software licensor, because modified software does not represent the source, origin and quality control of the author. However, removing trademarks from unmodified products can also be a violation of the law. I’ve been writing about this topic for a long time, though, so I won’t prattle on.