Every .dk domain that delegates its _acme-challenge name to 3e5d9fc3-2d94-45dd-a5d4-7deb289613cd.acme.aau.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.