Apple Seeds Panther build 7B21, new Xcode
Apple provided testers and developers with a new pre-release version of Mac OS X 10.3, code-named Panther. The update was marked build 7B21, the first "B" series Panther build to be seeded. A new version of Xcode Suite was also seeded, with "issues addressed in almost every component," according to the read me. Read more about it at ThinkSecret.