RPO means "Regular Production Option", which is a fancy way of saying the different choices you can make when you buy a car.
Think of it like choosing your own ice cream sundae! You can choose what kind of ice cream you want, what toppings you want, and even if you want a cherry on top.
With a car, you have options too. You can choose what color you want, what kind of wheels you want, what kind of sound system you want, and even what kind of engine you want! These are all RPO codes that come with your car.
So, when you see a code like "ZL1" or "L88" or "GT500", those are all RPO codes that tell you specific things about the car's options. Just like how "chocolate syrup" might be a topping code for your ice cream sundae!
Overall, RPO codes are just a way for car companies to give you lots of options and let you choose exactly what you want in your car.