What is this part that is welded to the vacuum line going into the intake ? Looks like it has two vacuum line connections out of which one is just open / unused (circled in red) ?! Is this how its supposed to be or am I missing something ?
I am the second owner of the car so dont have any idea if there is any history behind this.
Please advise! Thanks!

 

This is a breather for the transfer case, it must be open.

 

That seems to be it! Thanks!
Do these ever need to be checked or go bad ? Any quick easy test for it while I am at it ?

 

The only way to check it is to remove the filler plug on the transfer case and blow into the breather, but I don't think there's any point in that, it's a primitive part that never breaks.