/usr/s390x-linux-gnu/lib32/libgfortran.so.3 is in lib32gfortran3-s390x-cross 6.3.0-18cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/s390x-linux-gnu/lib32/libgfortran.so.3.0.0
/usr/s390x-linux-gnu/lib32/libgfortran.so.3.0.0