HTTP status codes (resent)

Last week I erroneously sent this message to the wrong address -
therefore nobody commented to it :-( 

Here there is another try:

% One way or the other, I believe there is going to need to be an IANA registry.
% Private codes don't work too well, as two different people might
% still happen to choose the same one.

Maybe we could set up a single HTTP code (x99) for private extensions,
and write that whoever wants to answer with a x99 code MUST add a 
header like

Message-Subcode: <any string>

This way, things could run more smoothly, even if at the cost of 
some tens of bytes. Of course, we still need a registry, so that 
extension blessed by someone will be neatly allocated. 

cioa, .mau.