Looks like the original is under a permissive ("BSD-style") license, in which case they almost certainly can distribute it under any license they want.
They can distribute it, but this looks like it's changing the license. I thought that only the owner can change the license of the copyrighted file?
Now, you can include BSD-style files with GPL ones without issue--that's true. But I thought you can't change the license of a file from BSD to GPL unless you are the original owner.
(IANAL) BSD-style licenses generally only require that the file and its derivatives retain the original authors copyright notice. Distributing it under a different license still allows you to fill the original requirements, so there's no conflict there. Or from a different angle, what exactly is the difference between including a BSD file in a GPL file vs including a BSD file in an empty file and then licensing the result as GPL?
Edit: Does it help if I tell you that more precisely they aren't relicensing the file but merely stacking licenses on the file? The process is purely additive.
Now, you can include BSD-style files with GPL ones without issue--that's true. But I thought you can't change the license of a file from BSD to GPL unless you are the original owner.