/usr/share/doc/python-bzrlib-dbg/changelog.Debian.gz is in python-bzrlib-dbg 2.6.0+bzr6593-1ubuntu1.6.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/python-bzrlib-dbg/../python-bzrlib/changelog.Debian.gz