/usr/lib/x86_64-linux-gnu/libFOX-1.6.so is in libfox-1.6-dev 1.6.50-1+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libFOX-1.6.so.0.0.50
/usr/lib/x86_64-linux-gnu/libFOX-1.6.so.0.0.50