--On Tuesday, 21 July, 2020 22:41 +0100 Paul Smith
The former ones tell me something. It may or may not be that
useful. It may nor may not be true, but it tells me something.
The latter ones tell me (the recipient) nothing at all. I'm
honestly not sure why the latter data is in the headers at all.
It *may* be that if I ask for support from Paypal about an
email, they'll ask me 'What was the
"X-PP-Email-Transmission-Id'' header in that message? But I
seriously doubt that would happen. If it did, then adding that
header is OK, otherwise, no. In any case, the Message-ID
should be sufficient for them to trace it if that's what they
need to do.
The former set may be more useful if it was tagged with WHICH
server added those headers, but that's it.
Is it the case that, if we wanted to make these useful, we'd be
considering a way to make those fields into trace fields, with
all of the time-stamping and server (or other supplying entity)
information that implies? Non-trivial work and something that
would certainly have to be done as a new Proposed Standard or
Experimental spec, not in 5321bis, but maybe an interesting
FWIW, it is a question: I have no idea whether it would be a
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