Requested copy of an off-list mail:
What if it were named msg-id-interior or some other
variant instead of msg-id-core?
Well, I strongly support to have only one <msg-id-core>
concept everywhere, creating a new name for the 2822upd
variant does not exactly help with this final goal.
Are the folks wanting the 2822upd variants (sic!) sure
that they really want them ? Or do they actually want
some <id-left> "@" <id-right> excluding "obs" ?
If it is the latter, the proposed syntax doesn't exclude
"obs" and won't help them. If it is the former they can
simply say <id-left> "@" <id-right> without creating
a new shorthand for this construct.
Third possibility, they actually want <msg-id-core> as
specified in RFC.ietf-usefor-usefor. That should get
its number this year, the only MISSREF is in Last Call.
Fourth possibility, they want the future "real thing",
a <msg-id-core> limited to what both 2822upd minus obs
*and* RFC.ietf-usefor-usefor allow.
For the fourth option they should wait like everybody
else until there is an IETF consensus about the future
unification. We are near, but not yet there.