/usr/s390x-linux-gnu/lib/libnss_files.so.2 is in libc6-s390x-cross 2.24-10cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/s390x-linux-gnu/lib/libnss_files-2.24.so
/usr/s390x-linux-gnu/lib/libnss_files-2.24.so