- to have a way to find if there is an existing header that serves some
given purpose.
Problem is, absent good design review and an agreed-on specification,
reuse of existing fields can cause interoperability problems.
Precedence, Priority, and Return-Receipt-To are all examples.
And X-Sender (or, if you prefer, X-X-Sender). And X-Priority. And
X-Sun-Charset, X-Sun-Content-Encoding, X-Sun-Content-Length,
X-Sun-Content-lines, etc. Even Encoding, which has an experimental
specification but no generally agreed-upon use, is interpreted differently by
different agents.
Do we really want to get into this?
Ned