initramfs-tools 0.120ubuntu8 (s390x binary) in ubuntu xenial

 This package contains tools to create a bootable initramfs for Linux kernel
 packages. The initramfs is a compressed cpio archive. At boot time, the
 kernel unpacks that archive into RAM, mounts and uses it as initial root file
 system. The mounting of the real root file system occurs in early user space.
 klibc provides utilities to setup root. Having the root on MD, LVM2, LUKS or
 NFS is also supported.
 Any boot loader with initrd support is able to load an initramfs archive.