-/// An update generated by the underlying Channel itself which contains some new information the
-/// ChannelMonitor should be made aware of.
+/// An update generated by the underlying channel itself which contains some new information the
+/// [`ChannelMonitor`] should be made aware of.
+///
+/// Because this represents only a small number of updates to the underlying state, it is generally
+/// much smaller than a full [`ChannelMonitor`]. However, for large single commitment transaction
+/// updates (e.g. ones during which there are hundreds of HTLCs pending on the commitment
+/// transaction), a single update may reach upwards of 1 MiB in serialized size.