Universal Scene Description
Universal Scene Description is a framework developed by Pixar. Also known as Crate files. "It is a system for encoding scalable, hierarchically organized, static and time-sampled data, for the primary purpose of interchanging and augmenting the data between cooperating digital content creation applications."
USD & USDA files are text files and begin with the ascii
USDC are binary files and begin with the hex values
PXR-USDC in ascii.