Current "continuous" and "longpoll" (and potentially text/event-stream feeds; see
COUCHDB-986) are selectable only via a "feed" query parameter. Ideally, it would be best for these feed types to be made available based on Accept headers sent with the request. Browsers and "lesser" HTTP clients who don't offer header alteration or addition could fall back to the current "feed" query param as needed.
This addition would allow clients to send "Accept: text/event-stream" (or other mimetypes) with a _changes feed request and receive the stream body in that mimetype. The current "continuous" and "longpoll" responses would need their own registered mimetypes (rather than just text/plain or application/json). These mimetypes could still be used in conjunction with the "feed" query param.