/usr/share/ddupdate/plugins/ is in ddupdate 0.5.3-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/ddupdate/plugins/changeip.py
/usr/share/ddupdate/plugins/default_if.py
/usr/share/ddupdate/plugins/default_web.py
/usr/share/ddupdate/plugins/default_web6.py
/usr/share/ddupdate/plugins/dnsdynamic_org.py
/usr/share/ddupdate/plugins/dnsexit.py
/usr/share/ddupdate/plugins/dry_run.py
/usr/share/ddupdate/plugins/dtdns.py
/usr/share/ddupdate/plugins/duckdns.py
/usr/share/ddupdate/plugins/duiadns.py
/usr/share/ddupdate/plugins/dynu.py
/usr/share/ddupdate/plugins/dynv6_com.py
/usr/share/ddupdate/plugins/freedns.py
/usr/share/ddupdate/plugins/freedns_io.py
/usr/share/ddupdate/plugins/hardcoded_if.py
/usr/share/ddupdate/plugins/hardcoded_ip.py
/usr/share/ddupdate/plugins/ip_disabled.py
/usr/share/ddupdate/plugins/ip_from_cmd.py
/usr/share/ddupdate/plugins/myonlineportal_net.py
/usr/share/ddupdate/plugins/no_ip.py
/usr/share/ddupdate/plugins/now_dns.py
/usr/share/ddupdate/plugins/system_ns.py