s390x/ubuntu:16.04 on Docker Hub

With https://hub.docker.com/r/s390x/ubuntu/, the first Ubuntu 16.04 image just appeared on DockerHub
Update 4/17: image size is consistent with x86, but not what I wrote initially, at least the virtual image size when deployed locally.

linux1@ibm-test-0126-0802:~> docker run -ti s390x/ubuntu:16.04 bash
Unable to find image 's390x/ubuntu:16.04' locally
16.04: Pulling from s390x/ubuntu
ddcc0f08d7af: Pull complete
645160adc108: Pull complete
d3d23e5703c9: Pull complete
bc7cf9496bff: Pull complete
Digest: sha256:be2000c082624d4fe033ebac3c3df2e5d40310ac6f32c990fc5b25a02acebdd7
Status: Downloaded newer image for s390x/ubuntu:16.04
root@a90f97cccb0a:/# cat /etc/os-release
NAME="Ubuntu"
VERSION="16.04 (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
UBUNTU_CODENAME=xenial
root@a90f97cccb0a:/# apt-get update
Get:1 http://ports.ubuntu.com/ubuntu-ports xenial InRelease [247 kB]
Hit:2 http://ports.ubuntu.com/ubuntu-ports xenial-updates InRelease
Hit:3 http://ports.ubuntu.com/ubuntu-ports xenial-security InRelease
Get:4 http://ports.ubuntu.com/ubuntu-ports xenial/main Sources [1099 kB]
Get:5 http://ports.ubuntu.com/ubuntu-ports xenial/restricted Sources [5461 B]
Get:6 http://ports.ubuntu.com/ubuntu-ports xenial/universe Sources [9844 kB]
Get:7 http://ports.ubuntu.com/ubuntu-ports xenial/main s390x Packages [1469 kB]
Get:8 http://ports.ubuntu.com/ubuntu-ports xenial/universe s390x Packages [9399 kB]
Get:9 http://ports.ubuntu.com/ubuntu-ports xenial-updates/main Sources [40 B]
Get:10 http://ports.ubuntu.com/ubuntu-ports xenial-updates/restricted Sources [40 B]
Get:11 http://ports.ubuntu.com/ubuntu-ports xenial-updates/universe Sources [40 B]
Get:12 http://ports.ubuntu.com/ubuntu-ports xenial-updates/universe s390x Packages [40 B]
Get:13 http://ports.ubuntu.com/ubuntu-ports xenial-security/main Sources [40 B]
Get:14 http://ports.ubuntu.com/ubuntu-ports xenial-security/restricted Sources [40 B]
Get:15 http://ports.ubuntu.com/ubuntu-ports xenial-security/universe Sources [40 B]
Get:16 http://ports.ubuntu.com/ubuntu-ports xenial-security/universe s390x Packages [40 B]
Fetched 22.1 MB in 7s (2776 kB/s)
Reading package lists... Done
root@a90f97cccb0a:/# apt-get install nginx
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  fontconfig-config fonts-dejavu-core geoip-database libexpat1 libfontconfig1
  libfreetype6 libgd3 libgeoip1 libicu55 libjbig0 libjpeg-turbo8 libjpeg8
  libpng12-0 libssl1.0.0 libtiff5 libvpx3 libx11-6 libx11-data libxau6 libxcb1
  libxdmcp6 libxml2 libxpm4 libxslt1.1 nginx-common nginx-core sgml-base ucf
  xml-core
Suggested packages:
  libgd-tools geoip-bin fcgiwrap nginx-doc ssl-cert sgml-base-doc debhelper
The following NEW packages will be installed:
  fontconfig-config fonts-dejavu-core geoip-database libexpat1 libfontconfig1
  libfreetype6 libgd3 libgeoip1 libicu55 libjbig0 libjpeg-turbo8 libjpeg8
  libpng12-0 libssl1.0.0 libtiff5 libvpx3 libx11-6 libx11-data libxau6 libxcb1
  libxdmcp6 libxml2 libxpm4 libxslt1.1 nginx nginx-common nginx-core sgml-base
  ucf xml-core
0 upgraded, 30 newly installed, 0 to remove and 22 not upgraded.
Need to get 14.9 MB of archives.
After this operation, 58.0 MB of additional disk space will be used.
Do you want to continue? [Y/n]