What it does — Catch Up
You asked:
What does Catch Up do?
Catch Up turns board changes into a visual map of what needs attention.
Catch Up clusters the changes on a board visually and summarises each cluster: what changed, who did it, where you were mentioned. You get an at-a-glance picture on the board itself rather than a list in a panel, and a clear "you're all caught up" end state.