Every .dk domain that delegates its _acme-challenge name to 4306cf25-12e9-4982-929d-2b7a22201a4a.11.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.