/usr/lib/freeradius/rlm_sql_postgresql.so is in freeradius-postgresql 2.1.12+dfsg-1.2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/freeradius/rlm_sql_postgresql-2.1.12.so
/usr/lib/freeradius/rlm_sql_postgresql-2.1.12.so