In this screenshot you can see the Model Y area on the left side of the road and some new sugar going on the right side.
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I always thought that this will be a parking lot for employees and/or for produced cars. But the piledriving activity there suggests that something will be constructed there. Maybe a multi-storey car park, but maybe something else...
Never seen any leaked construction plans for a building on this not insignificant area. We didn't see this for the power station and steam buildings either, but those are way smaller.