Long time reader, first time poster and
D23 expo attendee. There was some additional information that was linked to on a D23 Facebook post:
Advance Online Reservations Overview
For the very first time at D23 Expo, advance online reservations will allow guests to make complimentary advance reservations for select D23 Expo experiences for themselves and another D23 Expo Guest. Reservations are available for select panels only and are offered on a first-come, first-served basis, subject to availability. Advance online reservations for all event days will be available starting
Friday, August 16 at 12:00 p.m. PT/ 3:00 p.m. ET until reservation capacity is full. If guests do not receive their desired reservation(s), there will be standby queues at all StorePass, StagePass, and Talent Central locations.