/usr/share/doc/gnat-8-sjlj-powerpc-linux-gnuspe is in gnat-8-sjlj-powerpc-linux-gnuspe 8-20180414-1ubuntu2cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gcc-8-powerpc-linux-gnuspe-base