/usr/lib/sitesummary/ is in sitesummary-client 0.1.28+deb9u1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/sitesummary/collect.d/
/usr/lib/sitesummary/collect.d/debian
/usr/lib/sitesummary/collect.d/debian-edu
/usr/lib/sitesummary/collect.d/nagios
/usr/lib/sitesummary/collect.d/siteinfo
/usr/lib/sitesummary/collect.d/system
/usr/lib/sitesummary/nagios-plugins/
/usr/lib/sitesummary/nagios-plugins/check_cups_queue
/usr/lib/sitesummary/nagios-plugins/check_etc_hosts
/usr/lib/sitesummary/nagios-plugins/check_etc_resolv
/usr/lib/sitesummary/nagios-plugins/check_kernel_status
/usr/lib/sitesummary/nagios-plugins/check_ldap_root
/usr/lib/sitesummary/nagios-plugins/check_shutdown