Jan is talking about the drain pipe on the Corona pump, not the vapour return line.
You are an attentive reader, duckling
If "Corona" is really the term for the "new" Italian-made mechanical fuel pump, than it does have a drain outlet, pointing downwards.
Now to answer the question: as of now it leads nowhere though I am not really happy about that. I am even less happy about the overflow lines from the carb float chambers, they dingle around loosely with all the risks that involves. So I was thinking of some common solution for all three, only it seems the carb overflow lines are rather delicate and better not extended.I heard of some people sticking them into the air filter, sounds queer to me but I am no engineer.
And I am reluctant to install a fuel return line, it would have to go all the way to the header tank which is located behind and slightly below the pilot's seat. Plus I would have to tinker with the plumbing near the aluminium header tank and that's a scary idea to me. A vent line would have to go to one wing tank, with a separate "tap" so as to be above the fuel level - even less attractive.