This Connector draws a Bezier curve with two control points. You can provide a 'curviness' value which gets applied to jsPlumb's internal voodoo machine and ends up generating locations for the two control points.
How 'curvy' you want the curve to be! This is a directive for the placement of control points, not endpoints of the curve, so your curve does not actually touch the given point, but it has the tendency to lean towards it. The larger this value, the greater the curve is pulled from a straight line.
Optional value for a distance to travel from the connector's endpoint before beginning the Bezier curve.