Every .dk domain that delegates its _acme-challenge name to 4620b5de-3be3-4b07-9373-c7064dff5c79.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.