As shown below, my autofill in Mathematica showed an interesting function: DispatchQ. Yet, it does not appear in the Mathematica Documentation Center, a search for DispatchQ on the Mathematica Stack Exchange comes up with nothing, and even a Google search for "DispatchQ" reveals nothing I can see relating to Mathematica (though there is a link to a 1915 document from the New York Supreme Court).
Does anyone know what it is and why it isn't documented?

Trueif applied to aDispatchobject. – ciao Jun 26 '20 at 23:48/.for distinguishing rule lists andDispatches. – SnzFor16Min Jun 28 '20 at 07:31DeveloperPackedArrayQ` is a test used often by many that shows up. – ciao Jun 29 '20 at 04:49