Every .dk domain that delegates its _acme-challenge name to 626ccc65-51b0-4241-ab4a-c84b9fa5e624.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.