Every .dk domain that delegates its _acme-challenge name to 5c8c4191-86b8-4a0f-b2a1-c405bdffbeb2.2.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.