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