/usr/lib/x86_64-linux-gnu/libgnat-7.so is in gnat-7 7.3.0-16ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgnat-7.so.1
/usr/lib/x86_64-linux-gnu/libgnat-7.so.1