/System/Library/PrivateFrameworks/UVFSXPCService.framework/Versions/A/XPCServices/UVFSService.xpc/Contents/MacOS/UVFSService UVFS is a pseudo file system that sends file system requests such as read and write system calls to user-level file system daemons.
The binary is a part of UVFSXPCService private framework.