Help identifying vacuum line

[dannym]

Hello everyone,

I went to check the vacuum system prior to making transmission adjustments and was only getting 15" at the main to the shutoff valve.

I started checking lines going into the cabin and found when I plugged the brown? one in the picture the vacuum went right up to 20+". The line in question is shown in the attachment.

The manual says "To other vacuum consumers". Which is totally usless information.
Can anyone identify this line and tell me what it does?

Thanks

Danny