MQTT: What does /Ac/Out/S show?

MQTT Explorer shows these 2.

The first one is clear - what does the second one show? I am on a 1-phase system.

N/c0619ab3dxyzf/vebus/276/Ac/Out/P - AC Loads
N/c0619ab3dxyzf/vebus/276/Ac/Out/S - ???

Power Factor, I’ve always thought. Edit: WRONG, but related

It is apparent power measured in VA. power factor would be P/S, a number between 0 and 1.

Let’s see if someone can confirm.