Triage is a special function of Tabletop.Events that allows you to find, report, and remedy defects you find in your games. For example, someone might tear a box, rip a page of the manual, or bring back a game that is missing components. Triage helps you identify those problems, and manage them.
By default each game will be marked ready to be triaged after 3 checkouts. You can change this in Library Settings.
Games that have been marked for triage, appear under the Triage menu. You'll basically just cycle through each game until you have completed them all. Here's what the game triage screen looks like:
NOTE: A game can also be mini-triaged at check-in time.