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So, in the course of SR's mainquest we learn from Paarthurnax that the Elder Scrolls are (and I'm paraphrasing here) "leftover bits of creation".
Is it then not possible that these bits and pieces are the mysterious "creatia" harvested by White-Gold? That would explain why they're stored there, instead of a secret Mothpriest facility: Because White-Gold, besides formerly keeping the Mundus aloft, was/is also the miles-tall printing press for the scrolls.
There are further questions, natch. What are these leftovers/creatia exactly? Unused yet still bound-in-Mundus Earthbones? The missing bits of the Aedra? UNBORN OMNICONSCIOUS FOETAL-DIVINES?!!!