What is revolutional with AR Quicklook on iOS 13.4 ?
With iOS 13.4 Apple lifted the veil of some internals of its RealityKit universe.
Formerly their AR-Editor Reality Composer was exporting scenes only in a proprietary
.reality file format. And just a few users and designers used it to manually create and update scenes. And developers had no access to documentation and not a clue how to create those scenes with their own Code base.
With iOS 13.4 and the new release of Reality Composer with USDZ export the situation changed drastically.
USDZ files are just uncompressed zip archives containing one or more USD files (the binary form = .usdc) and folders with textures and sounds needed by the scene (aka USDStage).