Every .dk domain that delegates its _acme-challenge name to ccf1e293-9099-4b8e-a4f1-9e9a9a615a6a.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.