Every .dk domain that delegates its _acme-challenge name to f34c3460-7c75-44a5-a3c1-091de2f76e8a.c-8a1f.tx.auth.certifytheweb.com. 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.