+ /// Historically, [`ChannelMonitor`]s didn't know their counterparty node id. However,
+ /// `ChannelManager` really wants to know it so that it can easily look up the corresponding
+ /// channel. For now, this results in a temporary map in `ChannelManager` to look up channels
+ /// by only the funding outpoint.
+ ///
+ /// To eventually remove that, we repeat the counterparty node id here so that we can upgrade
+ /// `ChannelMonitor`s to become aware of the counterparty node id if they were generated prior
+ /// to when it was stored directly in them.
+ pub(crate) counterparty_node_id: Option<PublicKey>,