RE: Escaping things in element names

["Jon Hanna" <jon@xxxxxxx>]

There may be an argument made though for an element that encapsulates the X-
headers.
Since such headers are named by different (ad-hoc) decision-making processes
to the standard headers, it could be useful to define an element that
describes these such headers as name-value pairs. This would simplify the
job of validating messages since it reduces the possibility of unknown
elements being present in valid messages.

This would also have the advantage of covering the entire range of possible
valid headers.