Vac line identify

[Lowblock]

Hey guys, I have 2 e53's and both have the vac line that is attached to the small port on the bottom of the intake boot before the TB. One is a 12/02 build 4.4 and one is a 9/02 build 4.6. Looking through all of real oem diagrams I cannot find anything about this small hose. There are pictures of the boot that shows the small port on it but no hose attached. Ive tried searching over the interwebs and there are a few places that show the line attached, but not what it does, where it goes or the part number for it. I can probably fix the one on the 4.4 no big deal, but the one on the 4.6 was laying on the ground under the car (pack rats) and I have no idea where it goes to. I can get pictures if needed, someone else has to have come across this.

Thanks
Dave