#532 IESG ballot on draft-ietf-httpbis-p2-semantics-25, reason phrase optional?

Sean Turner asks:

> s6.1: Is it worth mentioning that the reason-phrase can also be not sent? I think that's elsewhere but it might be worth mentioning again.

AFAIU, the reason phrase is not optional, but it can be empty. Consider 
the ABNF in 
<http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p1-messaging-25.html#status.line>:

   status-line = HTTP-version SP status-code SP reason-phrase CRLF
   reason-phrase  = *( HTAB / SP / VCHAR / obs-text )

So it wouldn't be unreasonable for a recipient to split on the first two 
SP occurrences (and fail if there is none).

Best regards, Julian