What command to show selected objects or edges abutt?

rather than rely on eyesight, if I have two box like objects I need to be sure are abutting and not overlapping by a gnats whisker, what command will show that ?

and they are part of the same object so no moving and re snapping to be done.
boxes abutting test for



If they’re solid, BooleanIntersection will give you the overlapping volume. If the command fails, then the objects do not overlap.

If after that you run Intersect and you get an intersection curve, then they touch at least where the intersection curves are produced.