The Omni USD extension (omni.usd) is the Python frontend of omni.usd.core. It serves to load and initialize Pixar USD library, and Omniverse USD Resolver that supports opening USD from Omniverse/HTTP urls. It provides synchronous and asynchronous interfaces in C++ and Python to manage omni.usd.UsdContext, which will be introduced in section UsdContext. Besides those, this extension also provides common utilities and undoable commands for wrapped USD operations that can be shared for other extensions. It is the foundation component for all other extentions that need to access USD.