On this page:
The example is <div role="navigation" ...> containing a ul which contains the navigation links. Why not get rid of the div and put its attributes directly on the ul? The div seems like cruft to me.
Doing <ul role="navigation"> would replace the semantics on the <ul> (which has a default role of list), and thus break it. Applying to a wrapping <div> is the correct way to do this.