little help with locating hose under hood...

[apb306]

after doing work under the hood I managed to pull and unplug some type of hose and have no idea where it goes. There is nothing coming out or vacuum from it and after many attempts cannot find where it plugs in.
Need someone to look under their hood and follow it to tell me where it might go.
not sure but this might be related to my L/100km jumping from 12.1 to 13.7 in the last couple of weeks.