Say what the receiver of the Want- fields has to do

[LPardue]

From @jricher's WGLC review

§5: This doesn't really say what the receiver of the Want- fields has to do. If there's no obligation to fulfill it (which I think is the case), we should state that explicitly here.

We borrowed heavily the text from RFC 3230, we can add more clarification as suggested

[ioggstream]

@LPardue wrote in the mail

The Digest and Content-Digest sections state that a sender MAY send anything.
Additionally stating that there is no obligation to follow Want- fields SGTM.

Since RFC3230 does not specify that, server can implement any behavior (either 2xx or 4xx). See

• https://github.com/httpwg/http-extensions/blob/main/draft-ietf-httpbis-digest-headers.md#server-selects-algorithm-unsupported-by-client-ex-server-selects-unsupported-algorithm
• https://github.com/httpwg/http-extensions/blob/main/draft-ietf-httpbis-digest-headers.md#server-does-not-support-client-algorithm-and-returns-an-error

We decided to avoid normative statements on that, but I'm open to suggestions.

[ioggstream]

@jricher does #1835 (comment) clarify your question?

[ioggstream]

closed via #2097