What is stopping point?

Hello, developers.
I’m reading the ardupilot code to understand its detail flight control logic.

The thing that makes me confused is “Stopping point”.
What is it for?
Just for braking, during Auto flight?

I thought the stopping point is a kind of “sub” waypoint to move drone toward main waypoint, not to exceed the velocity or acceleration limitaion.
But, there is a “advance_wp_target_along_track” function in AC_WPNav.cpp, which is built up with similer with stopping point function.

Is there any one know about this?