Weird! Spoon wings usually show up more as high downforce variants. RB's is almost dead straight for Spa. But Merc is also running a more aggressive wing, so there might be some method to the madness. If I were to hazard a guess I might be able to come up with a reasoning for Williams, as they've struggled with balance and consistency and have nothing to lose in the standings, taking a hit on Vmax, might not bother them so much.
It's hard to tell for sure, but the floor appears to be revised.
the four immutable forces: