Every .dk domain that delegates its _acme-challenge name to ffdf00ce-4d1c-4102-8553-e52f92c9a33c.10.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.