/usr/share/doc/strongswan-plugin-xauth-noauth/changelog.Debian.gz is in strongswan-plugin-xauth-noauth 5.3.5-1ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/strongswan-plugin-xauth-noauth/../libstrongswan/changelog.Debian.gz