It wasn't clear to me what kind of monitoring equipment is being used to gather this data, or whether it's just being manually gathered and reported by each system owner.

If the former, I'd like to get the generic equipment to use to monitor my heat pump system, and if the latter I wonder if the resulting inaccuracy results in improbable outliers like the system with 6.0 COP.

EDIT: it's a bit buried, but the systems are monitored using Open Energy Monitor (https://docs.openenergymonitor.org/applications/heatpump.htm...), and it seems like heatpumpmonitor.org was created by them.