collision.relativeVelocity given just before or just after impact ?

all in the question.
https://docs.unity3d.com/ScriptReference/Collision-relativeVelocity.html gives an example where sound is playing if this value is high enough, but this is only true if "collision.relativeVelocity" is taken just before impact.
However after some testing i suspect this is not the case.

 

I think it's neither. I believe it's in the frame when the impact happends.