/usr/lib/x86_64-linux-gnu/libzmq.so.5 is in libzmq5 4.2.5-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libzmq.so.5.1.5
/usr/lib/x86_64-linux-gnu/libzmq.so.5.1.5