Dear David, thank you very much for your fast response.
I don't know how the descriptions from stable are updated (point release maybe), but the Sid one is correctly displayed in German:
http://packages.debian.org/de/sid/libbsd-dev
Are the description from Squeeze correctly displayed in a German environment (apt-cache show libbsd-dev)?
Unfortunately the result of $ apt-get update $ apt-cache show libbsd-dev was an English description. Cheers, Martin