/usr/lib/x86_64-linux-gnu/libcg3.so is in libcg3-dev 0.9.9~r10793-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libcg3.so.0
/usr/lib/x86_64-linux-gnu/libcg3.so.0