/usr/share/doc/libgfortran3-dbg-ppc64el-cross is in libgfortran3-dbg-ppc64el-cross 4.8.2-16ubuntu4cross0.4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gcc-4.8-powerpc64le-linux-gnu-base