Even if it can be demonstrated that some unextended viewers show many
header lines instead of just the last few, I think we should avoid
cluttering the old header lines (From, To, etc).
Erik,
Most unextended viewers display everything they get, trace fields and
X-blather and all. Let's not debate whether it should be that way, it
really is.
Proposals in the style of yours still have the advantage that, to an
"old" reader, the gibberish is isolated in headers separate from to
conventions "From", etc. ones. I suggest that the alternate idea of
moving this interpretative, non-address, information, out of the headers
entirely, putting them into a (perhaps special and always first)
RFC-XXXX body part is a member of the same family of proposals: slightly
better for some reasons, perhaps slightly worse for others.
But the problem with both of these is one of creating and maintaining
bindings between the "real" (822) headers and the extended ones,
especially as mail is gatewayed into non-SMTP systems, forward, resent,
and replied to.
And, whatever you design as an introducer for this sort of thing,
someone will have used it in an atypical context, e.g.,
Subject: Problem discussion message number *3*
This, of course, is also a problem shared by the "put it here, reference
it from there" systems unless one can know for certain that XXXX mail
and not 822 mail is being processed.
john