I have never heard of such a brake system component.
A Google search finds nothing called an anti-chatter valve.
I did find an anti-shudder valve but that is for diesel engines, to shut off air to the cylinders to prevent shut down run on.
The Pantera technical manual refers to that component as an “equalizer”.
On Steve’s website it is referred to as a “pressure control valve”.
But “anti-chatter valve “??
A proportioning valve by any other name is still a proportioning valve.