/usr/share/doc/gfortran-5-mips64el-linux-gnuabi64 is in gfortran-5-mips64el-linux-gnuabi64 5.3.1-14ubuntu2cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gcc-5-mips64el-linux-gnuabi64-base