Viewports in Campaign Cartographer
After typing out a bit I realize this might be more of a "feature request", unless CC3 has this ability and I passed over it.
I would define a "viewport" as a boxed area which displays another section of the sheet, but at a different scale, or a different rotation.
This means you could work in full scale on one section of the sheet, and if that layout was maybe at 1/4 scale, or 8x scale for a blowup box, on your final output it would automatically do it within this box which has an active "view" on the defined viewport target.
It would be especially cool if the viewport could refer to other CC3+ projects, which could assist city maps where people want to take the "roof" off and see inside their building - though I could understand that maybe it renders that "image" once and isn't constantly up-to-date without explicitly updating the view. (resource wise)