Moderators have access to a history of events for every user account. This contains fairly important stuff like suspension, moderator messages and annotations, but also some stuff that moderators almost never need to know.
The biggest offender in terms of noise is the "moderator recalcs rep" message which in the case of a well-behaved user often makes up at least 90% of all messages in their history. I'm not exactly sure when it happens, but it is triggered very regularly whenever the user's reputation is adjusted automatically by the system. It is of no use to a moderator.
This is how a typical history from a well-behaved and very active user looks:
The exception would be events that indicate that serial voting was reversed or votes invalidated by SE, but I'm not sure how exactly those appear in the history and if they are a different event type. Those should still appear in the history.
But the automatic rep recalcs should go, they only add noise.