ThinkSecret reports that Panther 7B28 and Jaguar 10.2.7 have been seeded.
The update is said to bring extensive changes to various services (listed in the article) in the Operating System... but no specifics of the exact changes are given.
ThinkSecret also notes that Version 10.2.7, build 6R34 has also been seeded.
Mac OS X 10.2.7 (codenamed Smeagol) will be the release that accompanies PowerMac G5s. First reported in early June, this newest update provides PPC970/64-bit support to Mac OS X, and should be the shipping Operating System on the new PowerMacs.