/usr/lib/quagga/libquagga_pb.so.0 is in quagga-core 1.1.1-3+deb9u2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/quagga/libquagga_pb.so.0.0.0
/usr/lib/quagga/libquagga_pb.so.0.0.0