And the winner is...

#550000 sndfile-programs: ..trying to overwrite '/usr/share/man/man1/sndfile-cmp.1.gz', which is also in package libsndfile1 0:1.0.20-2
http://bugs.debian.org/550000

I missed it by exactly one when filling #549999: ITP: libindicator -- panel indicator applet - shared library[/b]
http://bugs.debian.org/549999

:(