This is an approximation of where the center of a ‘pinch’ gesture occurs, and is used internally by StereoKit for some tasks, such as UI. For simulated hands, this position will give you the most stable pinch location possible. For real hands, it’ll be pretty close to the stablest point you’ll get. This is especially important for when the user begins and ends their pinch action, as you’ll often see a lot of extra movement in the fingers then.
Found an issue with these docs, or have some additional questions? Create an Issue on Github!