[mail-vet-discuss] What is the A-R header really for?

[Eliot Lear]

So I think in summary we need clearer text on the applicability of this
header, the jist of which should be that MUAs SHOULD NOT in general
process it as authentic information.  I still believe that certain
environments SHOULD strip out others' headers, but this is environment
specific.  As John wrote, MTAs will do what they will do.

None of this obviates the need for more work on mailing list exploders
and the like that Charles alludes to.

Eliot