Identify where or what a water pipe might lead to?

[Ramprat]

I recently changed a countertop in my kitchen and while doing so took the opportunity to check the incoming water pipe that's hidden behind the cabinets, while doing so I noticed something that seemed odd, the incoming water pipe seems to split 3 times after the stopcock, the first split leads to the kitchen sink so that's fine, the second goes into the wall but at an angle that's straight up and I know that leads to the bathroom upstairs and from there feeds the boiler and cold taps, the 3 split seems to go into the party wall at a downwards angle, It could be totally normal but I'm at a loss to think what this could be leading too, as far as I'm aware the neighbours don't share our water feed so I don't think its that.

Is there a logical explanation or easy way to work it out without ripping the cabinet out, Its not a big deal but I'd kind like to know what's were in the house as we keep finding unexpected things, being an old military base house, while renovating over the years.

See attached pics

 

[Aquarius]

A garden tap install perhaps? Is this a flat or house/bungalow?

 

[Ramprat]

A garden tap install perhaps? Is this a flat or house/bungalow?

No outside tap in my garden

yes that would help wouldn't it its a mid terrace. Also not sure if its relevant but it's ex military, use to be base housing

 

[Aquarius]

Could be an old feed? Only confirmed way would be to disconnect it and then find out if or what no longer works.