The ARR stuff was explicitly designed so that implementations that didn't
want to implement it could ignore it safely; it's hard to undo that.
Leave it alone for the standard
That's all I'm asking, and seemed to be the consensus of the group -
document subpacket 10 as "reserved for future use" with no other
comment. This did not seem to be what Jon Callas decided at the IETF
meeting.
As Ian Grigg said, documenting the Additional Receipient Request in a
neutral way is impossible with the conflicting variety of opinions in
this group. The only fair way to deal with it is to not mention it at
all.
Ian.