Lenco gearbox airpots - plumbing of air lines

I have brought a lenco three speed gearbox and the air pods have been plumbed up with nylon quickrelease fittings into the centre of the top of the airpods, beside it there is also has another nylon fitting for air.
What is this for ?, can someone explain to me, Is it for some other function thanks.

 

Where is the fitting?
If its coming out of the top of the lenco case near the pods its a vent
If it is a "t" fitting that is in-line with the supply line for the pods it could be use for a gauge.

 

Lenco Line

If it is a pressurized line, it could have been used to trigger an air activated device in the fuel system.

 

or ignition retard

 

lenco Air Pods fitting

There is a fitting for the air line from the lenco shift buttons in the centre of the pod and beside it towards the outer circle of the pod is another fitting which when you take the top circlip out when air enters the centre fitting it also will go out the other fitting, must be to activate a fuel management or retard setup as advised by several of you's, through it must be for something like this. Thanks for the information.

 

someone probley done it that way instead of using a T fitting if you dont need it just put a plug it