Not the normal folundations, the ones at the exterior walls at 1:11:26 in @DeaconElie 's posted video, I think the launcher video shows them being placed and they are really tall being one piece. My guess is it might be something not released yet like @Immortalowl said.
I like the look of slanted walls for some buildings but I can’t replicate it with current building pieces, that oine might work.