Old building basement built in 1910 water shaft

Attached are better photos. Of the shaft. I hope you can see more there.

Wow, that is really very special. Of course, the first question you would have to clarify is where the pipes come from and what comes out of them? Maybe it would be easiest to just interview the previous owner again? Rainwater from the roof maybe?

That looks like an improvised pump sump into which water may possibly be introduced from outside due to lack of connection to the sewer system. The yellow corrugated pipe is the classic "drainage pipe" that homeowners always use to divert larger amounts of water in the ground. The corrugated pipe is officially not approved for this purpose, but traditionally no one minds. Therefore, I would question the functionality of such a drainage system. Nevertheless, water can seep through this pipe from the hillside into the shaft.

The gray pipe is an HT pipe for drainage lines im house. It is not approved for installation in soil or concrete constructions; instead, KG pipes (orange/blue/green) from DN 110 with greater stiffness are used there. However, I have already found such HT pipes in self-built rainwater main lines.

Observe whether water flows through these two pipes during heavy rainfall or whether it also enters through soil joints or wall joints. If water accumulates, you can consider installing a submersible pump that then drains into the sewer above the backwater level,

The gray pipe is an HT pipe for

The gray one comes from the basement room next to the stairs, there is a drain, according to the seller his parents always stored coal there. However, I myself don’t know where the yellow corrugated pipe comes from and neither does the seller. Unfortunately, there are no more building plans etc. from the house, as they were lost in the 2002 flood in the city. The house was built in 1910, so the yellow corrugated pipes would not have existed then, so apparently that must have been added later at some point. The building is fully connected with sewage etc. Around the house there are two inspection shafts at each gutter that lead into the public sewer. The red hose on the right only leads up to the garden so that the hose can be laid through it.

I have to say, both pipes do not come from the slope side, the slope side would basically be on the left when facing it. However, the two pipes would be on the right.

I would ask around in the neighborhood with old houses and also inquire about water problems during rain and backflow from the sewer. Such a system must have a background; nobody builds that out of boredom.