To me it appears quite clear that Broadcom is distributing a GPL'd
file, and thus has to turn over the source code.
Now you may argue this exempts them from this (but it probably still
* Firmware is:
* Derived from proprietary unpublished source code,
* Copyright (C) 2000-2003 Broadcom Corporation.
* Permission is hereby granted for the distribution of this
* data in hexadecimal or equivalent format, provided this copyright
* notice is accompanying it.
But what about in versions distributed for years where that was not
included? That text above is recent addition. To my surprise when I went
to download the driver on their page I found I had an old
~/devel/broadcom directory with a file linux-7.3.5.zip containing
files timestamped from 2004 (the above copyright was added in 2005).
Here, the bcm5700-7.3.5-1.src.rpm file was tagged "GPL".