/usr/share/strongswan/templates/ is in libcharon-extra-plugins 5.5.1-4+deb9u4.
This file is owned by root:root, with mode 0o755.
..
/usr/share/strongswan/templates/config/
/usr/share/strongswan/templates/config/plugins/
/usr/share/strongswan/templates/config/plugins/addrblock.conf
/usr/share/strongswan/templates/config/plugins/certexpire.conf
/usr/share/strongswan/templates/config/plugins/dhcp.conf
/usr/share/strongswan/templates/config/plugins/eap-aka.conf
/usr/share/strongswan/templates/config/plugins/eap-gtc.conf
/usr/share/strongswan/templates/config/plugins/eap-identity.conf
/usr/share/strongswan/templates/config/plugins/eap-md5.conf
/usr/share/strongswan/templates/config/plugins/eap-mschapv2.conf
/usr/share/strongswan/templates/config/plugins/eap-radius.conf
/usr/share/strongswan/templates/config/plugins/eap-tls.conf
/usr/share/strongswan/templates/config/plugins/eap-tnc.conf
/usr/share/strongswan/templates/config/plugins/eap-ttls.conf
/usr/share/strongswan/templates/config/plugins/error-notify.conf
/usr/share/strongswan/templates/config/plugins/farp.conf
/usr/share/strongswan/templates/config/plugins/ha.conf
/usr/share/strongswan/templates/config/plugins/led.conf
/usr/share/strongswan/templates/config/plugins/lookip.conf
/usr/share/strongswan/templates/config/plugins/tnc-tnccs.conf
/usr/share/strongswan/templates/config/plugins/unity.conf
/usr/share/strongswan/templates/config/plugins/xauth-eap.conf
/usr/share/strongswan/templates/config/plugins/xauth-generic.conf
/usr/share/strongswan/templates/config/plugins/xauth-pam.conf
/usr/share/strongswan/templates/config/strongswan.d/
/usr/share/strongswan/templates/config/strongswan.d/tnc.conf