Coolant leak, need info - what is this part called?

This looks like coolant heat pipes heading down towards the exhaust or they get heated and sent back up to make heat real fast in the car just a guess by your pictures that's what it looks like so either one of the pipes has a pin hole in it or the hose connection on the Barb is leaking past the Barb and running down the hose and dropping where it can at that bend good luck.

 

That pair of pipes you're looking at is what has callout 87208 here, 87208-47020. Somebody has one on eBay for $27. It's $96 list price at the dealer.

Although it's listed in the parts catalog as a "heater hose", this particular "hose" is a pair of metal pipes.

As Tombukt2 suggested, there could be a leak either at where those lower hoses (real hoses) attach, or somewhere above, with the leaked coolant running down the outside of the pipes to where you're seeing it.

If it were my car, I'd start by just examining and redoing all the connections where (real) hoses join to those pipes. There are five places, the top and bottom ends of both pipes, plus you'll notice in the picture one of them has a tee branch off the side.

The clamps where the hoses attach should be the springy kind Toyota uses, which put a steady clamping force on even as the rubber gets compacted there over time.

If anybody did any work with those hoses in the past, you could find some spring clamps got replaced with the worm gear kind that tighten with a screwdriver. Those can be more trouble as, unlike the spring clamps, they don't tighten themselves over time as the rubber of the hose compacts.

There might be nothing more needed than attention to the hose connections. Or, if you find some pinhole or crack in one of the pipes, you can buy that pipe assembly and replace it ... or replace one of the hoses, if the trouble is there.

The dealer can also sell you the right original spring clamps, if you need those.