Interesting I wonder if that part of the GPL has been tested in court?
Jeff McMorris

“How can the license then be changed to something more restrictive than the license it was released under?”

The same way that if Microsoft incorporate some BSD-licensed code into Windows, they can release it under a fully proprietary license. BSD and MIT (and other permissive licenses) permit you to impose additional restrictions. The original copyright holder (and anyone else) can obviously still choose to provide the original code under the original license.