On the classification sources page in Admin, it would be handy to have the selection from the DefaultClassificationSource visible somehow. Maybe a simple line of text at the top of the page, with a link to the system preference? Or some sort of icon or highlighting in the Classification Sources table?
We did this for 36510 to indicate the CircControl on the circulation rules page, so it seems like it would be relatively easy to show this on the Classification sources page with a link to the syspref.