Most-recent cohort this update's operator addressed. Read by the
dm . pronoun verb. null until the operator has sent.
Stamp this update's inbound cohort. Called by the sending comms
update on each recipient's comms update after tell composes the
frames.
Send a private message to one or more targets over the Aether,
on behalf of this update's host (the operator). Single-target
produces the classic tell rendering; multi-target stamps the
full cohort + optional meta.channelId and adds a "(also to: …)"
hint to per-recipient frames.
Most-recent cohort that addressed this update's operator. For a 1:1 inbound this is
[sender]; for a multi-party DM it's[sender, ...siblings]so a reply-all has every party. Read byreply.