/usr/share/doc/phonon-backend-gstreamer-dbg/changelog.Debian.gz is in phonon-backend-gstreamer-dbg 4:4.7.0really4.6.0-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/phonon-backend-gstreamer-dbg/../phonon-backend-gstreamer/changelog.Debian.gz