ᐅ Thin copper pipe cut through next to the fireplace, house built in the 1960s

Hello, I have rented a house from the 1960s and am currently making an opening between the kitchen, where the chimney is located in the corner, and the living room.
The lintel is positioned just before the fireplace in the wall (living room wall = the same wall where the fireplace is).
While working on it, I accidentally cut through an uninsulated copper pipe about 8-10 mm (0.3-0.4 inches) in outside diameter and approximately 3 mm (0.1 inches) in inside diameter, running vertically in the wall about 2 cm (1 inch) next to the fireplace. It comes down from the ceiling and appears to continue all the way below the floor into the basement.

My question is: Could this have something to do with the fireplace? Should I be worried because of the oil heating system, or what could this pipe have been used for?
I cannot determine where it comes from or where it leads to. Everything is still working as before.

Thanks in advance for the shared knowledge.

Hello,

check if there was an oil stove in the room. These were previously supplied with oil through these thin pipes. However, they should lead to the attic, at least that was the case for me.

Regards

@abrafax951 Please upload a picture, so it’s easier to assess.