In the toolbar, what are the “cheese wedge” shaped things on the elbows & tees and how do I hide them?

The “cheese wedges” are pieces of geometry pointing to the work points of each elbow and tee. They enable the modeler to easily snap dimensions when dimensioning to work points and are recommended while annotating any plan or section. They can easily be hidden in the Model Categories in the Visibility/Graphic Overrides of any view.