Round tables are typically feedback sessions so the DM can hear from the actual people who work in stores instead of just from SMs. My DM does a quarterly round table with SSVs from her district and one for baristas. They might have questions about how well your store is running, what ideas or questions you have about operations, what you feel like you need to do your job effectively, how well your SM supports you and the team, etc etc. It's a discussion, not a quiz.

I suggest reflecting on how supported you've felt as a trainer, specifically, before you go in. Do you feel like your training hours are scheduled at a good time or are you struggling to train in between people running around? Do trainees get enough hours with you or are they half-assed and flung to the wolves? Are you able to focus on training when you're scheduled to do that, or do you have other tasks that are inhibiting your ability to really connect with the baby barista? Then go in with an open mind and your listening ears on, and be ready to give honest answers and ask honest questions.