Does anyone happen to know where Pokemon X/Y save data is actually stored?

Does the game use the cart/card to save or is everything on the 3DS itself?

I'm wondering how going from 3DS to 3DS would work in the event of a replacement or repair.

Would swapping the cart to another 3DS move the save data over?
Would System Transfer work with Pokemon X/Y save data, or would you need to actually go through Nintendo support?

I know there were some issues with backing up or transferring saves on ACNL, and it's assumed X/Y uses the same type of lockdown.

If anyone has any experience with it, that would be neato.