Clear side marker lights
It's an antiquated north American regulation requiring an orange reflector to be visible when looking at the car directly from the side. Maybe it was from when accessory bulbs were incredibly dim and colored glass bulbs didn't exist yet. The US is notorious for being way behind when it comes to vehicle lighting regulations. We now have LEDs. Aside from maybe some anal retentive safety inspector in some authoritarian county somewhere, it's something that no one cares about once it's gotten through customs.