Every .dk domain that delegates its _acme-challenge name to e40c8548-8f21-472d-b81e-f7de43bddaa2.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.