/usr/share/man/man1/x86_64-linux-gnu-gnat-5.1.gz is in gnat-5 5.5.0-12ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man1/gnat-5.1.gz
/usr/share/man/man1/gnat-5.1.gz