Builds of the highly anticipated Mac OS X 10.3.1 Update have begun to surface over the last 24 hours. The most recently know build (7C103) weighs in at just under half a megabytes and appears as a package upgrader.
Mac OS X 10.3.1 About Dialog
According to sources, the build patches 'webdav' resources in the 'sbin' and 'System' directories, as well as significantly modifying the 'IOStorageFamily.kext' extension. The build also updates Panther's login window application and brings the Mac OS X Terminal application up to version 1.4.1.