When someone leaves a position, rarely are they leaving a completely cleared out INBOX. Things are in progress; DECISIONS are in progress.
One of the best ways an onboarder can orient to a new role; and one of the best ways the manager of that onboarder can help—is to understand the major and minor decisions she is stepping into. Maybe not that week, but soon.
Best completed pre-departure by the job incumbent, DECISIONS IN PROGRESS previews pending decisions along with other needed decisions expected further down the road.