The opening lets the handle of a mug, travel cup, or handled container sit down between the cup holders while the main body of the cup remains supported by the circular holder. This can make it easier to fit certain large or handled cups without forcing them into a standard round holder.
So it isn’t a missing piece or a defect—it’s a small piece of practical car-interior design. 🚗🥤
One caveat: the exact purpose varies by vehicle; on some models, a similar opening is simply part of the cup-holder insert’s shape or provides clearance for removable inserts.
