Rawhide is the development tree for the Fedora Linux distribution. It is continually revised, with software being added, removed, and updated. In many cases, this software is made of CVS, Subversion or Git snapshots.
Rawhide is not meant to be used as a production system. It should only be used as a development testbed. However, many developers and hackers from the Fedora Project use it as their primary operating system.