Also see the repository info page for additional info.
No news is good news. Rebased from last 2.6.37. Contains: CKO Colored Kernel Message Output, ISOFS write bit, VT preferences through sysfs, ttyrpld rpldhk driver, keep CD try unlocked, 2009s leap second fix, TCP-Hybla selected, 1G LOWMEM, NF Extension Overview, VT SISO hack, AUFS.
The kernel-source package provides a sparse source, much like
kernel-devel package. That is, only the source files
(mostly header files) that are needed for external module compilation are
included. More often than not, users have repeatedly screwed their
kernel source installations, so the side effect of not being able to run
oldconfig/cloneconfig is a welcome one.
Some module packages, even if they are generally compatible with 2.6.31, make a total mess out of their build system and thusly can fail. One example is when they try to look for source files they should never be touching in the first place (usbip did this).
Other packages, such as nvidia, need a bunch of extra parameters if it does not find the locations correctly (hell know why). I have no idea what crime they commited, but at least I worked around it with my .src.rpms of it.
Many modules compile without extra work — such as ndiswrapper, lirc, etc. As do nvidia and vmware, as far as kbuild is concerned, the "fixed RPMs" mentioned above relate to its RT kernel capability.