This tarball contains the Darkness 1.6 32-bit linux build, a copy of the Valve Source Dedicated Server for SDK 2013 Multiplayer and 32-bit libraries that will help it run on 64-bit systems.
If you're familiar with SteamCMD and recent SRCDS installation methods, you don't need this tarball. Simply untar the darkness 1.6 Linux 32 build into your srcds folder, create darkness/cfg/server.cfg, perform the usual srcds fixes, and go!