/etc/freeradius/sites-available/ is in freeradius 2.1.12+dfsg-1.2ubuntu8.2.
This file is owned by root:root, with mode 0o755.
..
/etc/freeradius/sites-available/README
/etc/freeradius/sites-available/buffered-sql
/etc/freeradius/sites-available/coa
/etc/freeradius/sites-available/control-socket
/etc/freeradius/sites-available/copy-acct-to-home-server
/etc/freeradius/sites-available/decoupled-accounting
/etc/freeradius/sites-available/default
/etc/freeradius/sites-available/dhcp
/etc/freeradius/sites-available/dynamic-clients
/etc/freeradius/sites-available/example
/etc/freeradius/sites-available/inner-tunnel
/etc/freeradius/sites-available/originate-coa
/etc/freeradius/sites-available/proxy-inner-tunnel
/etc/freeradius/sites-available/robust-proxy-accounting
/etc/freeradius/sites-available/soh
/etc/freeradius/sites-available/status
/etc/freeradius/sites-available/virtual.example.com
/etc/freeradius/sites-available/vmps