[zaarn]

IIRC Google's implementation is more of a "DNS as JSON over HTTPS" while the RFC standardizes "DNS wire format over HTTPS".

I believe Google implement theirs first but I also think using the RFC format is easier (as evidenced by the OP tunnel)

[tssva]

There is no RFC. There is an internet draft making its way through the DNS over HTTPS working group.

The current draft requires support of the application/dns-message media type which is basically an standard dns request base64 encoded. The draft also allows for other media type but does not define them.

Although the Google implementation isn't compliant with the draft since it significantly pre-dates efforts to standardize dns over https, a draft compliant server can accept and return JSON formatted queries.

I will agree that the dns-message format is easier in the case of a traditional dns resolver but it is not easier in all cases. JSON is easier for a web app to produce and consume which is the use case the Google dns over https project was originally designed to address.