Every .dk domain that delegates its _acme-challenge name to c9495aa1-7a3f-4fb7-bcbb-dec0c2962f95.1.authorize.certificatemanager.goog. 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.