This container can be pulled via:
  docker pull registry.opensuse.org/suse/templates/images/sle-15-sp1/base/images/suse/sle15:15.1
  docker pull registry.opensuse.org/suse/templates/images/sle-15-sp1/base/images/suse/sle15:15.1.4.300

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.