No water used for mopping

I wonder if it’s dry mopping. When it finishes, it says to empty wastewater, but the last couple weeks there has been nothing in it.

I wondered the same thing and you can change how much water it uses. So max it had nothing left but when I put it on med there was so much left and it wasnt dirty at all..I dont really understand the mopping feature. Doesn't seem like it uses enough water and like where is the dirty water going beside the tiny pad?