Universe File Extensions

There are two different file extensions for a Universe file, .unv and .unw. What is the difference?

If we are working on a Universe named 'Order', the file name when working in Design is 'order.unv'. The unv extension is the Design extension used "locally".
As soon as you export the Universe to the Repository the file extension changes to .unw. The file is then saved in a directory named after the object id (e.g. '855263') which is placed under the Input File Repository Server (FRS) directory.
If you open CMC and look at the properties for that Universe the path could be something like
'frs://Input/a_123/012/013/855263/order.unw'.