Every .dk domain that delegates its _acme-challenge name to fd3a2319-b1e7-49e6-8bca-af5d9bb6a6b8.auth.acme-challenge.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.