The reason is that package lists and individual packages
are processed in different dependency resolution "transactions"
by mkimage; thus if packages (the more precise form of specifying
the contents) come first they can't override the lists appearing
later, and that's wrong: we should be able to specify the more
generic things and then pinpoint the specifics.

This became apparent while authoring [[Mkimage/Profiles/m-p/howto]]
asked for by drool@.