Currently it's not possible to export a list of event registrants with the answers from the custom registration fields (registration responses).

But our customers are always requesting it, because they would need it for catering, t-shirt size, newsletter opt-in etc.:

For example they want to have a list, where they can filter on the preferred lunch option (meat, veggie, vegan).

Currently they have to search via advanced find the contact which has an event registration with the registration response in the field response the value. That's okay to do for customer which do not have a lot of events, but if you want to manage all your events via Dynamics Marketing that's not really user friendly and really a lot of work to do.