This container can be pulled via:
  docker pull registry.opensuse.org/devel/kubic/containers/container/kubic/kube-apiserver:v1.28.15
  docker pull registry.opensuse.org/devel/kubic/containers/container/kubic/kube-apiserver:v1.28.15-6.137

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.