Question How is LAST_SEEN_TIMESTAMP determined

I'm new to working with Unity Analytics and I'm trying to understand how LAST_SEEN_TIMESTAMP is set in the Events table. It seems like it is set 4 hours after the last session event.

Can anyone help me understand what it means to be "last seen" and how that is different from the Event timeframe?

I'm mainly looking to find out the last date and time a player played the game and figure I should use EVENT_TIMESTAMP, but this LAST_SEEN_TIMESTAMP is confusing.