I'm not sure what they call that type of plumbing line, it mostly just gets in the way, and if you touch it, we'll snap off at all those joints.

But the line is to run coolant over top of the metal piece being cut. We don't use it very often at all, or never at all. You can however flex it over top of the work piece, to run out of water oil mix to cool off the metal as it's cutting.

This saw has three ways of running coolant over top of the work piece, One at the start edge of the cut, but you can see hose in this photo, that one seems to cool off the work piece the best for us. There is one at the tail end of the cut too. And then there's this one that we don't really use at all. Thought about capping it. But you never know one of these days we might get some large alloy steel to cut on the saw, where this extra cooling hose might come in handy.

This photos shows the hose to the inlet on the lead edge of the cut.

That's the one we use most

But the hose that you cropped, it does just look cool, and it's fun to play with, but very hard to clean all the grease off of it, I debated on taking it up to the sink and letting it soak in some sunlight detergent, but instead I cleaned other parts of the saw.