/usr/share/doc/libxgks-dev/changelog.Debian.gz is in libxgks-dev 2.6.1+dfsg.2-3ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libxgks-dev/../libxgks2/changelog.Debian.gz
/usr/share/doc/libxgks-dev/../libxgks2/changelog.Debian.gz