Fair enough. Although I'm not sure why one would want that behaviour given that there is no guarantee of ordering when a particular JSON file is processed with any other library.
I don't know what they do with it, but it's handy for writing tests against an expected JSON file: assert json.dumps(expected, sort_keys=True) == json.dumps(obj, sort_keys=True) # where expected was json.load()-ed and obj was produced by the function