SOA record
soa.present
The SOA defines the zone: who is primary, who to contact, and the replication timers.
A longer write-up of this check has not been published yet. The report itself shows the raw evidence behind every result, which is usually the fastest way to see what was measured.
Run this check on a domain
SOA record is one of 49 checks in every report, alongside delegation, mail authentication, TLS and registration.