Reaction forces on unconstraind entities

What are the physical meaning of reaction forces enlisted on unconstrained entities?

I run a static analysis on a L-shaped solid part, with two holes fixed in the short side and loaded with a force (1000 N)

at the long side's edge.

Reaction forces on the fixed holes are coeherent wih the load but what are the reaction on the short side's external face?

SolidworksSimulation