The export setting's advanced options name the contentsOnly option
"Ignore overlapping layers" and offer Include bounding box only when
every selected layer is a text layer. A setting that already has Include
bounding box on still shows the option, so it can be turned off, and the
export still applies it. The saved keys and the contentsOnly and
includeBoundingBox params of export.add, export.update and file.export
are unchanged.
Every catalog's "Contents only" row becomes an "Ignore overlapping
layers" row.