The probe that reads data from the points along the trajectory is simply called the tracer, but a more informative name would be something like dataProbe which is a name we've decided to use in Natural Selection. Would it take a lot of restructuring to call this a dataProbe?
From https://github.com/phetsims/projectile-motion/issues/219, @arouinfar had a review comment like:
I'll get on it!