The first Catalyst 13.8 Beta brought full support for the OpenGL 4.3 Khronos specification, Linux 3.10 kernel support, SLES 11 SP3 OS support, and various bug-fixes -- including many driver fixes for Valve's Source Engine games and other titles available on Steam.
With Catalyst 13.8 Beta 2, we don't exactly know what's been changed. AMD has yet to publish a change-log for today's Linux beta driver update. One can generally presume though that AMD at least managed fixing some OpenGL bugs within this release. If we manage to get a change-log on today's Linux Catalyst beta we will pass it along.
Today's AMD Catalyst Linux graphics driver update can be downloaded for Linux x86/x86_64 from this forum thread.