Its an engine, but it is a ALPHA of it, to help get it along financially and for some already running projects on it (like the TitanIMs work on a mil-sim). There is no API yet, so if ya want really do something more deep in it, ya better write Cameni an PM or better an mail for deeper discussion. Otherwise, its just used now by some folks on the forum on theyr own little model-import,, but on a free-volunteer basis for our own enjoyment.
As for real release, count on few years of needed development still, till Outerra is fully market-rife whyte all the tools for its potential engine costumers.
But as i said, if ya really have a deeper plan ... write Cameni personally for some discussion (he cant say all things in the forum and some licensing stuff is still murky as its just a alpha-state product).