>
>>
>> A resource has to exist first, before it can support PATCH.
>>
>
> Says who?
>
Common sense? Clearly-defined method semantics is part-and-parcel of a uniform interface. If we're going to muddy the waters by allowing partial PUT (or PUT no content to DELETE), and PATCH to create a primary resource (not sayin' PATCH can't result in a /previous-version resource being minted), then I guess HTML was right all along to only bother defining GET and POST in forms.
>
> Some origin servers support use of the Content-Range header field
> (Section 14.4) as a request modifier to perform a partial PUT, as
> described in Section 14.5.
>
Ugh. There's some wording above that, about how a service SHOULD use POST instead of PUT; I'd suggest (sometime in the future if PATCH is ever officially added) similar wording about SHOULD use PATCH. Some origin servers treat a zero-payload PUT as a removal request; similarly, some wording about SHOULD use DELETE could clarify.
I managed to watch a lot of golf this weekend while reviewing the latest HTTP drafts. Aside from the above, the only other editorial suggestion I have would be to add "8.4.1.4 Brotli Coding".
-Eric