/usr/lib/ipsec/libipsec.so.0 is in strongswan-plugin-kernel-libipsec 5.1.2-0ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ipsec/libipsec.so.0.0.0
/usr/lib/ipsec/libipsec.so.0.0.0