The goal of Orion is to build developer tooling that works in the browser, at web scale. The vision behind Orion is to move software development to the web as a web experience, by enabling open tool integration through HTTP and REST, JSON, OAuth, OpenID, and others. The idea is to exploit internet design principles throughout, instead of trying to bring existing desktop IDE concepts to the browser. See the Orion wiki for more information about Orion.
Orion source code is available in an Eclipse Git repository, and there is also a mirror on GitHub. For complete details on getting the source and getting setup to develop Orion, see the Orion wiki.
Bug reports and patches are welcome in bugzilla.