/usr/lib/x86_64-linux-gnu/libcgns.so is in libcgns-dev 3.3.0-5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libcgns.so.3.3
/usr/lib/x86_64-linux-gnu/libcgns.so.3.3