The next three pics are of a kitchen sink drain. The vent looks wrong, The drain pipe is 2" goes to the basement across the joists. 30’ run to it’s own 2" stack that the homeowner made. It discharges to a floor drain that was probably used for gutters back in the day. The vent pipe is 11/2" and exits the roof. The owner decided to bypass the main 3" stack which would have shortened the run by 15’.
Anyone have a good narrative for this?