I've been servicing the novatech freehub on my Kona cyclo-cross bike after a particularly filthy ride. When removing the freehub I noticed this tiny Allen bolt by the inner pawls of the freehub. When I found it, it was partially unscrewed and loosely holding a small tube on the inside, however I don't know what it is! As far as I can tell this is the only function it does, as it does not affect the pawls engaging in the freehub.
Blue arrow is pointing towards it.
What is it, what does it do, and how tightly does it need to be done up?!