/usr/share/doc/xtables-addons-dkms/changelog.Debian.gz is in xtables-addons-dkms 3.0-0.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/xtables-addons-dkms/../xtables-addons-common/changelog.Debian.gz