I know there is a Disable Masters custom parameter in the Font tab of Font Info where masters can be manually added by typing in the name.
Would it be possible to add a feature to disable masters directly from the Masters tab, perhaps with a checkbox?..similar to how instances can be disabled with the Active checkbox in the Export tab.
In addition, would it be possible to add a custom parameter to a master which would hide it from the UI of the main editor (Layers Panel and Masters Icons)?
That works already with a little help. You might want to add the
Custom Parameter “Enforce Compatibility Check” with an unchecked box.
But I agree that it might be optimal, if that would be the default without any extra custom parameters.
I +1 all your requests, and as a workaround tip: Add a Custom Parameter “Master Color” and make the disabled ones Red or sth. That way they shout at you when you have a disabled master active in the view.