1999 S80 vacuum hose at air filter housing

[ralphrash]

I am trying to do some basic maintenance on my 1999 S80 (not turbo) since being out of the car repair "business" for 40 years (Yikes, what a surprise!). I removed the air filter housing a few days ago and when I got back to my work, I couldn't locate one of the vacuum hoses I removed from the front of the air filter housing (the one on the right as you look into the vehicle from the front). Does anyone know what it does and what I need to do -- other than plug it -- to avoid some issue now that it is gone?

Thanks,

Ralphrash