Every .dk domain that delegates its _acme-challenge name to c14e6352-21f2-4c76-b176-8759f48a4a1b.auth.acme-challenge.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.