Jeremy keeps pushing out new X.Org Server 1.9 stable updates to bring XQuartz fixes for Apple and various other bug-fixes for users of the xorg-server under Mac OS X, Linux, and other operating systems. With the Mac OS X 10.7 developer preview that Apple began seeding to developers last week, X.Org Server 1.9 can in fact be found.
For X applications on Apple's operating system, this developer preview build is X.Org Release 7.5 with X.Org Server 1.9.4. The build date is 2011-02-19.
Can anyone guess where Apple's Lion will next be found? Yes, Mac OS X 10.7 is making its way to OpenBenchmarking.org.