/usr/lib/x86_64-linux-gnu/libownet.so is in libownet-dev 3.1p1-2ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libownet-3.1.so.1.0.0
/usr/lib/x86_64-linux-gnu/libownet-3.1.so.1.0.0