The project's housekeeping is under System activity, the other choice on the right of the bar.
System activity holds, for example, work sessions that changed nothing, shown as Work session (no changes), knowledge imported, changes of objective not tied to a session, the other steps of a question in Conversations (assigned, taken, a clarification requested, deleted (cancelled), restored or added to Planning), other system events and changes to the principles and rules that agents keep in the project's manifest, which are not those of the Rules tab. The start and the end of a session are not rows of their own: they are steps inside the session's entry, in its technical details.
Some records are never rows at all: each file written appears inside the work session that wrote it, and technical records such as agents connecting or waiting are left out. Changes of managers are shown only to the project owner. See How do I see only one agent's or team member's work, or only the last week?.