What is the difference between ‘session_start’ source/medium attribution and ‘event’ source/medium in GA4 Explorations?

Question

Google Analytics GA4 — Hard

What is the difference between ‘session_start’ source/medium attribution and ‘event’ source/medium in GA4 Explorations?

Accepted Answer

Session_start source/medium in GA4 is the initial traffic source for a session, applying to all events within that session. On the other hand, event source/medium reflects the last non-direct attribution at the event level, potentially showing a different source/medium for conversion events due to the attribution model.