/usr/lib/x86_64-linux-gnu/libgnatvsn.so is in libgnatvsn5-dev 5.3.1-14ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgnatvsn.so.5
/usr/lib/x86_64-linux-gnu/libgnatvsn.so.5