While verifying drivers/net/usb/ in the kernel I came across a firmware file without license information, kawethfw.h. The accompanying kaweth.c file is license under GPLv2 or later, and while it thanks two people for providing the firmware, it doesn't specify a license for it.
I looked through the deblob script Brian linked to recently, and it mentions this file in the "Not Removed" section, saying that it's not in kernel 2.6.23; I think maybe they couldn't find it though because they looked in the wrong location. They list it as being located at drivers/usb/net/kawethfw.h, but its actually at drivers/net/usb/kawethfw.h (net and usb are reversed).