Every .dk domain that delegates its _acme-challenge name to 2138feaa-ed5f-4691-944c-bf9a9ce03f66.cfargotunnel.com. 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.