Not sure where people are getting that the extras are on DVD for this? Since this is basically a repackage of the discs from the individual releases, and the extras are on BD for those, it really wouldn't make sense for them to be on DVD here. I expect all 11 discs to be blu-ray.
On the store's page, it mentions DVD on top of the extras, so maybe those are on DVD. It doesn't make sense to me either, so I hope it's just a typo.