Which index holds the fleet Healthy/Unhealthy status?

Hi

Fleet agents have dashboards. You could check the visualisation on which indices they are built.

Based on some of the data, you could probably find out things too by querying your elasticsearch on the logs-* (Kibana) data view to get a more specific index.

Good luck!
Christof

PS: Some time ago I looked into the general health status of my stack, but it seems that value is always calculated on the fly. So not sure if your health statusses are stored..