It's just like the existing Waveshare display hat (same connector, similar button layout) but obv bigger. Also it has a wider aspect ratio (320x240) instead of the current square screen. The v0.8.6 release accounts for the wider screen layout.

SeedSigner (the man) worked on the design and created a new enclosure for it. The first round of sales will help him recoup the cost of getting the boards made. After that I believe the plan is to open source the design.