Every .dk domain that delegates its _acme-challenge name to d972ebbe-4df7-48c6-81e0-f7f9e67e2f41.acme.aau.dk. Such CNAMEs hand DNS-01 certificate validation to a shared service, so this list shows who issues TLS certificates through it. Data comes from our own scanners, which re-resolve every .dk domain in the zone roughly once a week.