I'll answer the question myself by providing an example I saw elsewhere, which a...

daneel_w on Feb 7, 2023 | parent | context | favorite | on: DNS0: The European public DNS that makes your inte...

I'll answer the question myself by providing an example I saw elsewhere, which also illustrates that their "default" resolver differs from the curated "zero" resolver:

  dig @193.110.81.0 uni.cf a
  
  status: NOERROR, ANSWER: 2
  IN  A  67.199.248.12
  IN  A  67.199.248.13
  
  
  dig @193.110.81.9 uni.cf a

  status: NXDOMAIN, ANSWER: 0
  IN  A