Anyone have any insight on the interchangeable wing tip/removable bay as shown in this video at 12:15?

https://youtu.be/qvLxuCYgXwA

Allegedly my kit has this as an option stuffed in one of the many boxes of parts, but I’d like to see the details on how it’s actually carried out in the build and used when complete. Anyone have this on theirs?

Thanks,
David