Every .dk domain that delegates its _acme-challenge name to 1d53053d-437a-4a9f-ac5a-555fcaab49cd.acmedns.infinityfree.net. 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.