This function appears only once in the doc.
Almost at the very end of the page :

It’s not listed in the ‘BezierCurve’ API.
What king of parameters does it expect ?
Does it actually exist, or never got implemented in Natron ?
Because script console says ‘BezierCurve’ object has no attribute ‘slavePointToTrack’.

It is not implemented anywhere, see Search · slavePointToTrack · GitHub

For me, it doesn’t make sense to attack a Bezier control point to a track. Better compute a transform from the tracks, and apply it to the Bezier. If you have an example project that you can share, we can put it in the tutorial

So, it should be removed from the documentation.