A hand signal given by a slower driver to indicate that a faster car behind them may pass on a specific side. This is the primary passing protocol in HPDE events and ensures safe, predictable overtaking.
The HPDE First Timers Guide describes the mechanics: "To give the overtaking car permission, you must give the driver a point-by. This may be a physical point of your finger out the window, either to the side you want the overtaking driver to pass on, or to where you're going to drive your car so the overtaking driver can pass on the opposite side of the track." The guide also addresses the nuanced situations: "There will come a time where one car is faster on the straightaways and slower in the corners, and another is the opposite. This makes the passing rules a bit less cut and dried, and it's where etiquette comes in. If your car has lots of speed in the straightaways but less in the corners, and you have a car behind you that could lap faster than you, let it go."