I believe the reference is to the ambient lighting found in the door handles of some models. It depends on the year of your X5 if you have this option. But there is an easier way to determine what it is, remember

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"What you hear in a great jazz band is the sound of democracy. “The jazz band works best when participation is shaped by intelligent communication.”
Harmony happens whenever different parts get to form a whole by means of congruity, concord, symetry, consistency, conformity, correspondence, agreement, accord, unity, consonance…….