Every .dk domain that delegates its _acme-challenge name to 290be204-2e62-4ccd-8c84-87a6a18679a1.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.