Without knowing for certain, it appears to be natural gas line with a couple of different valves and plugs. Be very careful with changing or touching these pipes, if they really are gas.

Thank you. We will not touch it.😁

Yes, almost certainly a gas line, perhaps for a furnace or other appliance that's no longer there. Next time you have a plumber in the house, have them check it for leaks around the fittings and to make sure it's all capped off properly.

In Russia, all gas lines had to be painted yellow. We got dinged on an inspection because the last half foot of the gas pipe going into our furnace was not painted yellow,

In Germany it even has to be RAL 1021 yellow, as I recall. lol