/usr/lib/libpolybori-0.5.0.so is in libpolybori-dev 0.5~rc1-2.1build2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libpolybori-0.5.0.so.0
/usr/lib/libpolybori-0.5.0.so.0