This container can be pulled via:
  docker pull registry.opensuse.org/devel/kubic/containers/container/opensuse/butane:0.21.0
  docker pull registry.opensuse.org/devel/kubic/containers/container/opensuse/butane:0.21.0-9.121
  docker pull registry.opensuse.org/devel/kubic/containers/container/opensuse/butane:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.