Amazingly, yes. The rear brake line is routed inside downtube, shifter cables are external, presumably to engage cable stop/minimize cable friction. If I had an aluminum touring frame, I would definitely cut big holes in the downtube just to hide a single housing. Cause we all know this will save 20g of weight, be super aero plus look cool. Besides, what could possibly go wrong from cutting holes at the ends of an aluminum downtube that will bend and twist thousands of times on every bike ride?