Looks like Scarbs has spotted Mercedes bulking out their rear bodywork for enhanced cooling:
https://twitter.com/ScarbsF1/status/428 ... to/1/large
Could it be that this is just precautionary? After losing running due to the fault FW, they're unlikely to want to risk overheating or running anything near the limit. I hope this is the case and that they can revert to their slimmer package at some point.
-Update- Actually it appears they had this same package on when LH crashed yesterday?
Could it be that this was on the car all along but is hidden in most pictures? Can anyone confirm if they have two different bodywork packages in that area?