Every .dk domain that delegates its _acme-challenge name to 38ccac19-0bab-4eca-ad12-94b1e28f08bc.acme.formula.nu. 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.