Internal Fuel pipe connections

Hello everyone,

This is my first post here so a little background. I have a 1997 ST2 10K on clock which has been standing for 15+ years. And I’m just trying to get it to run.
I have changedfluids (except fork), all filters and both timing belts.

Bike wouldn’t start and found a seized fuel pump and HEAVY varnish on internals and tank. Have cleaned or replaced everything in tank as necessary. left injectors at this stage, I might be lucky! (Duck for those pigs)!

So my question, the fuel breather bubbler pot on the fuel flange assembly has a hose barb on the top of it. None of my pictures or workshop manual show this area clearly enough to know what to do. Does a pipe connect to this or is it just left unconnected?

For additional info I can just make out that two pipes from the flange base connect to the filler neck and those have been connected up.

Thanks in advance