Help determine what is connected to the meter

Background: 2 years ago I bought an apartment, the repair has not yet been done. From the counter there was an output 2-wire wire with a switch like a sconce or lampshade at the end. There were no wires from the switch. Turn on / off - without any effect.

The time has come for checking the electric meter. I doubted, suddenly this is some kind of illegal connection and everything will be blamed on me. He took off the panel, there this wire is connected to other wires, also of some strange origin, which go under the wallpaper in the corner and beyond. I disconnected the wires from the switch, while one of the flimsyly connected wires went away, I did not remember where he was before.

Further, I suggested that it could be wires to an outlet that is nearby (I did not use it, although the outlet is solid, built into the wall, not temporary) - and for sure, it does not work. It turns out that after building the house, either the electricians connected the socket or those to whom the landlord rented the apartment (I didn’t ask him, he lives in another city, rented the apartment, did not live in it at all).

In any case, I’m interested in whether it’s legal to connect an outlet and what was powered from these wires. Or everything passes - it is taken into account through the counter, and there will be no problems. Thanks for the help!