Not too sure about this one from a copyright point of view, but .... I'm guessings its a bspc.exe -bsp2map conversion of q3dm4 (yep, from Q3A). The map has been converted into a CTF 2fort style level. There is a number of technical problems but the gameplay is pretty good.
Worth the download, but I will pull this map if it falls under any infingement of copyright laws.