This by itself just looks to me like someone getting rid of the old CVS comments that are messing up the headers. Maybe the problem is that younger people don’t recognize what a cvs header is?
The threading code does seem to be "similar" enough to warrant some investigation, but from the looks no license notice was "removed". Even the threading code in question has never had one, from the initial import from CVS/Subversion.
Making a mountain out of a molehill .... before the molehill is even there?
