/usr/share/doc/nautilus-dbg/changelog.Debian.gz is in nautilus-dbg 1:3.18.4.is.3.14.3-0ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/nautilus-dbg/../libnautilus-extension1a/changelog.Debian.gz