UI Blurring used in Paragon

Hello all.
Does anyone have an idea how they achieved the UI blur effect used in paragon? I’m guessing it’s some slate magic? Could anything similar be created using UMG? Here’s a couple of screenshots. In the first one, the part of the image behind the “Skin Sale” bit is blurred, and in the second screenshot, everything is blurred underneath. It looks amazing!

This was covered in the last live stream and will be available in 4.15.
Check it out (00:32): Twitch