I thought the current application determined what is displayed in that area? How do we know the Terminal won't cause the escape and FN keys to appear? Same for

I thought the current application determined what is displayed in that area? How do we know the Terminal won't cause the escape and FN keys to appear? Same for TextMate, Atom, etc.? Yes, Apple owns the default Terminal app so there is no controlling what happens with it (or is there, i.e., can you, via preferences define what you want to show up regardless of what the app chooses...). But the makers of TextMate, Atom, and IDEs can decide to make the function keys show up, no?