Older home with recent water proofing, drain tile installed is bsmt. The pictures show something special. The close up is what appears to be a connection the main waste line through the slab, The wide shot shows the sump pit and pump.
I have a theory about what they were doing here, but would like to hear from the assembled masses.
BTW, one of the pipes entering the sump was the bsmt sink drain line. Very special.