I noticed that Quad 9 is not able to respond to the spy.pet query:
$ dig spy.pet @9.9.9.9 +short
;; communications error to 9.9.9.9#53: timed out
But Cloudflare DNS is able to do it:
$ dig spy.pet @1.1.1.1 +short
104.26.0.165
104.26.1.165
172.67.74.73
And to be sure, I checked another domain with the same TLD to rule out the option that Quad9 is unable to handle the .pet TLD, but I received a correct answer…
$ dig hello.pet @9.9.9.9 +short
3.64.163.50
Does Quad9 censor DNS queries?
The ability to change address records at global scale is built into DNS. It’s not a new thing.
Nothing is “built into DNS”. DNS is a couple of RFCs that include specifications on how the thing should work. What features one implementation (software) has is decision of those who made it and nothing else.