[vonmoltke]

I believe the GP is referring to price look-up codes (https://en.wikipedia.org/wiki/Price_look-up_code). These are often applied via sticker to the produce, as shown in the Wiki images. Every self-checkout system I have used has allowed me to directly type in the PLU for produce, which is what a human cashier would normally do as well.

Additionally, my personal experience with things like this is that human cashiers aren't any better than me at looking up produce in the absence of a PLU code. In fact, I'm generally better because I know what I picked up (or intended to pick up), so I just look for the right name.