Hole in the very bottom of the coolant tank

[Jimme T]

I have 2 coolant tanks for gen1 and they both have a hole in the very bottom of the reservoir tank. It’s a factory hole but what goes in there? I’ve never noticed it before but I don’t think I’ve ever had one off until now.
I’m talking about the overflow hole just to be clear.

 

[Cfoldone]

When the pressure in cooling system is higher than the tank cap pressure blowoff the fluid will run out not spraying fluid around, just down passage through tank center towards outside. The cap has a spring loaded pressure valve, when you turn over the cap you can see it in center of threads. The tank cap opening has a channel surrounding the threaded opening. It drains out that hole in tank bottom. When I replaced my 07 tank because it was crazing (small crack starters) at engine rebuild when I removed it and looked... Well that's were my drip was from, the cap was small leaker. So tank wasn't cracked yet, just the cap was weeping fluid every once in a while.

 

[Jimme T]

Thank You. I know what it’s for I was just wondering if something goes in the hole to drain somewhere. Mine drains right on to the frame rail. Thought maybe there was an insert or something that would direct the antifreeze to drain somewhere else