They are mostly used for the JFK
to Europe routes. The only route that I can think of to Europe fomr JFK
that they don't use the 763 for is the JFK
route. They are good for the routes to Europe because they are only 2 classes and aren't overkill on capasity.
This flight is probably a repositioning flight, it's between two hubs and most widebodies on short hauls domestically(except DL ATL
-Florida) are for that purpose, repositioning.