Session Finder now searches inside the data layer, not only the events each destination received.
Until now a session search matched the hits sent to GA4, Meta or any other destination. Now it also matches what the page pushed into the data layer, so you can find the sessions where a purchase carried no order_id, or where a variable was set but never consumed by a tag.
Who it is for: anyone debugging an implementation from the source: the value the dataLayer held, and what each destination did with it.
Where: Session Finder, in the same search box. Docs: Session Finder.