Every .dk domain that delegates its _acme-challenge name to d43c883e-8e5b-4f56-9821-e18aea4e4e4e.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.