Every .dk domain that delegates its _acme-challenge name to ab3e9c07-a5d6-4c0f-978f-e833ce7253a0.auth.acme-dns.io. 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.