brake servo connection?

[autokunst]

I'm getting to know my new-to-me car, 1968 1600-2.  Not sure if the two-circuit brake MC is original to the car or an upgrade over the past 54 years.  But my question is what this open connection on the remote brake servo is, and shouldn't something be attached to it?  I tried searching and have not been able to find a diagram or example.  Thanks in advance for any clues!

Here's the culprit:

 

Two circuit MC below:

[Mark92131]

31 minutes ago, autokunst said:

But my question is what this open connection on the remote brake servo is

 

Not open, bleeder screw.

 

Mark92131

[autokunst]

17 minutes ago, Mark92131 said:

Not open, bleeder screw.

I should have deduced that.  Thank you for the quick reply!

[jimk]

Find a rubber cap like should also be on the bleed nipples on the brake calipers and rear brake cylinders to keep the dirt out. 

[autokunst]

Thanks Jim,

Yes, this afternoon I used a rubber vacuum hose cap after blowing/vacuuming the fitting out.

Stephen

[Gurmail]

That dual chamber M/C set up is original to your 1602.