This container can be pulled via:
  docker pull registry.opensuse.org/home/dirkmueller/branches/devel/unifiedcore/tumbleweed/containers/elemental3ctl:0_4.26-4.39
  docker pull registry.opensuse.org/home/dirkmueller/branches/devel/unifiedcore/tumbleweed/containers/elemental3ctl:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.