/usr/lib/x86_64-linux-gnu/liblinbox.so is in liblinbox-dev 1.3.2-1.1build2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/liblinbox-1.3.2.so.0.0.0
/usr/lib/x86_64-linux-gnu/liblinbox-1.3.2.so.0.0.0