Every .dk domain that delegates its _acme-challenge name to 09f6a3a9-8f9c-459f-b9a6-eeb77dbbf6b4.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.