As I commented yesterday in the YouTube video, this is an awesome and long time wanted feature. But there is one thing I would change at the moment: in the already published Collection's page, I'd prefer having the "Contents" tab's info anywhere else, not hiding the product's description by default. Maybe in the sidebar, before the "Available formats" section. Even embedded in the description box. I think that having the description below the preview images like in every other product is key. Anyway, great work.