Porsche is extensively testing this model.
This one appears to wear the same light concealment as other examples of the upcoming GT4 RS. The engineers continue to put a covering over the top of the front fenders that are likely concealing vents like the ones on the previous-gen GT3 RS.
There is also something affixed to the top of the windshield on the passenger side. This is likely a sensor of some kind or an antenna for sending back telemetry to the track-side engineers.
Compared to the standard 718 Cayman GT4, the RS gains NACA ducts in the hood and larger openings in the rear fenders. There are also now inlets occupying the back portion of the side windows. At the back, there’s a huge, swan-neck wing with similarly large endplates. For the full story and video, check out this article from Motor 1.