/usr/s390x-linux-gnu/lib/ld64.so.1 is in libc6-s390x-cross 2.27-3ubuntu1cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/s390x-linux-gnu/lib/ld-2.27.so
/usr/s390x-linux-gnu/lib/ld-2.27.so