Of course it is available; but because it keeps changing, it won't be provided as an archive file in the "Downloads" area. Instead, look in the
Code area.
Use an SVN client and do a checkout. For Windows, you may like TortoiseSVN which integrates into Explorer context menus of folders.
Note that you may not have the permission to use modded clients to log in to the PlaneShift game server if it enhances features in an undesired way.