Can someone tell me what the air bypass tube (connected vertically on the TB) actually does?

I'm trying to figure out a 60mm TB swap, and I've got a 7M TB with the coolant line almost identical. I know I'd have to ditch(or block off) the charcoal canister, but oh well.

The only odd ball I'm left with is the airb by-pass. The 7M TB has a line that originally went to the valve covers. So I'm guessing it was just a breather line. Both the 7M TB "breather line" and the 22RTE TB air bypass line connect into the TB before the butterfly valve. So I think it will work to just reroute the stock tube to that breater line.

But I'm still left with my original question: what does the 22RE/RTE air-bypass line actually do?

The first pic is the 7M TB(with the dangly thing), the second of my stock 22RTE TB.