Not just Boeing, Bombardier have the same thing. My understanding is the same as The_Cutest_of_Borg
, but we may be wrong.
In relation to the +, if it is the location of the wiring loom to the panel why do we(Pilots) need to know? Could it be the spot to make a "technical tap" if required
which could make Capt Claret's version more likely.
I like your version Kaptin M but I would have thought that the more modern panels would be produced in a mass 'jig' with mega accurate laser cutters.
Next
.