The Kernel 3.13 mailing list announcement is – as usual – not very detailed, and in any case only shows changes since the last ‘release candidate’ (-rc8):    http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg572887.html

For a much more detailed look at new features, etc., there is a very useful summary here:
http://kernelnewbies.org/Linux_3.13

And..  More specific architecture/driver change information, here:
http://kernelnewbies.org/Linux_3.13-DriversArch

Robert Gadsdon.   January 20, 2013.