The application-specific portion of the Touch Bar is obviously customizable and this seems to be well documented, but what about "system-wide" custom Touch Bar elements?
For example, if I have a button with specific functionality in mind that I think would benefit from being on the Touch Bar and available in all applications, hence would reside in the control strip portion, would it be possible to add this button to the control strip or is this portion of the Touch Bar closed to developers?
