/usr/share/doc/texlive-doc/generic/dehyph-exptl/projektbeschreibung.bib is in texlive-lang-german 2009-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/texlive-doc/generic/dehyph-exptl/../../../texlive-lang-german/generic/dehyph-exptl/projektbeschreibung.bib