Every .dk domain that delegates its _acme-challenge name to f1ce5dff-872d-4c5b-b95e-589f0ec7a03f.9.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.