This airplane uses mechanical linkages, rods and ball joints to operate its control surfaces. Read more about it in the topic link below. Also, my 300th upload to KerbalX!
https://forum.kerbalspaceprogram.com/index.php?/topic/166008-real-control-surfaces-a-study-into-the-magical-properties-of-the-stock-elevons/
Built in the SPH in KSP version 1.3.0.