Not sure how long this actually has been in the source builds of UE5, but I just stumbled upon it today and was really surprised. Very happy to see this and I really hope it makes it into release.
Should be really helpful for scenes with a lot of dynamic range that are difficult to expose.
Performance cost (for this shot) was ~0.13ms on a GTX1070
Thats awesome 
Finally something, thats closer to real eyes or HDRI effects. If this works from a dark place looking at a brighter place, then it also should be good for looking from bright outside places into dark rooms/caves too.
It does! I can’t post a screenshot at the moment but it works even better in that situation in my opinion.
I also find it helps a lot in smoothing out the exposure transitions so that it looks more natural as the camera moves between areas.
