Limitations and memory items make up the large bulk of the oral at the end of training. Most check airman will go system by system while pointing at a poster of the overhead panel. What's this switch do, what does this light mean, why does this switch have an AUTO position, that kind of stuff. The only thing I'd say might be a little tricky would be the slides for the preflight inspection. They might ask about cooling vents for FADECs or strobe power supplies. Some of the photos leave a bit to be desired. Most check airman also have a real boner for number of static wicks per surface and which ones may be placed on the CDL. Overall, no real gotchas as far as systems knowledge goes. Getting ready for sim, know the flows and calls down cold. It'll make your life a lot easier in the box. An hour or two of chair flying with a partner can work wonders to help it make sense.