Every .dk domain that delegates its _acme-challenge name to ac3427fb-d83d-4c42-bda3-6a2472f8cb4d.trustzonevalidation.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.