This is the top of the Subversion repository.

   trunk/ ......... The latest development sources.  When people say
                    "Get the head of trunk", they mean the latest
                    revision of this directory tree.

   branches/ ...... Various development branches.  Typically a branch
                    contains a complete copy of trunk/, even if the
                    changes are isolated to one subdirectory.  Note
                    that branch copies are generally removed after
                    they've been merged back into trunk, so what's in
                    branches/ now does not reflect all the branches
                    that have ever been created.

   tags/ .......... Snapshots of releases.  As a general policy, we
                    don't change these after they're created; if
                    something needs to change, we move it to
                    branches and work on it there.