/usr/lib/x86_64-linux-gnu/libguac.so is in libguac-dev 0.8.3-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libguac.so.5.0.0
/usr/lib/x86_64-linux-gnu/libguac.so.5.0.0