XRInteractionManager is allowed to call protected internal functions?

Just curious how the XRInteractionManager calls this function on an XRInteractionBase
ln 265

interactable.OnSelectEnter(interactor);

But the signature of this function is...

protected internal virtual void OnSelectEnter(XRBaseInteractor interactor) 

And if I try to call it (as an example), I get a protection level error. So how is the manager able to call this without compile errors?


The reason I'm wondering is I'm trying to make a set of input controls so I can use KB/Mouse to quickly validate basic interactions without needing a full VR setup on the PC.

Thanks!