/usr/lib/x86_64-linux-gnu/libnanomsg.so.0 is in libnanomsg0 0.5~beta+dfsg-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libnanomsg.so.0.2.1
/usr/lib/x86_64-linux-gnu/libnanomsg.so.0.2.1