/usr/lib/bareos/backends/libbareoscats-mysql.so is in bareos-database-mysql 16.2.4-3+deb9u2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/bareos/backends/libbareoscats-mysql-16.2.4.so
/usr/lib/bareos/backends/libbareoscats-mysql-16.2.4.so