Every .dk domain that delegates its _acme-challenge name to d78a8a92-14bf-4df8-a489-89d74cb4b709.acme-auth.itcn.dk. 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.