Quick Vacuum Line Question

[Clutch450]

So i noticed today that on the back side of my intake mani I had a vacuum nipple that was open. I can find it's source.
I was using the taboo speed shops vacuum diagram but can't seem to connect my open line to the diagram.

Here's a pic of it. I capped it off with the red cap. Just asking where it's supposed to feed to.
Thanks

 

[JayJones]

can you get a picture zoomed out a little bit

 

[TSITurbo95]

Looks to me it was going to the charcoal canister. If it is gone, might as well get rid of the rest of the vac lines.