[Yoda]

. . . I think that the right forearm also has "magic" throughout the downswing. It not only acts (together with the bent right wrist and PP#3) to direct the clubshaft into impact, but it also acts to keep the clubshaft on plane throughout the entire downswing. I think that's also part of its "magic".

[Additional bold emphasis by Yoda.]

Right you are, Jeff (as usual, after your own 'proof positives'). Moreover, the Right Forearm supports the On Plane Loading and Release motions of the Sweetspot (and #3 Pressure Point / Right Forefinger) without itself being On Plane.