Every .dk domain that delegates its _acme-challenge name to 4c12a08d-a1e7-4a5b-bc1e-a1e7539b3eaa.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.