/usr/share/doc/gnat-5-sparc64-linux-gnu is in gnat-5-sparc64-linux-gnu 5.5.0-12ubuntu1cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gcc-5-sparc64-linux-gnu-base
/usr/share/doc/gcc-5-sparc64-linux-gnu-base