/usr/lib/x86_64-linux-gnu/libgpac.so is in libgpac-dev 0.5.2-426-gc5ad4e4+dfsg5-1build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgpac.so.4.5.0
/usr/lib/x86_64-linux-gnu/libgpac.so.4.5.0