Among the many updates present on various cars at Melbourne, Red Bull certainly has one of the more interesting as the RB10 features a brand new rear wing endplate, including a new solution to reduce the drag induced by the rear wing.
The previously common solution, as seen on the inset, was to add gills on the high pressure side of the rear wing. These gills allowed some air to bleed off from the high pressure area in between the endplates to end up on the outer sides of the endplates. Red Bull's new endplate lacks these gills, instead adding 3 small apertures on the low pressure side of the rear wing. Here, air from outside the endplates flows through these openings into the low pressure area under the wing.
In both cases, downforce generated by the rear wing is marginally reduced, but the return is a less strong vortex on each side of the rear wing, resulting in less drag. What triggered this new design is unclear, but it is not unthinkable that the stronger DRS system has something to do with it.