The Lift Mechanism is maintaining the manually specified offtake (volume per time unit).
Liquid control is most common for producing wells, except the case when bottomhole pressure is being reduced by the downhole pump to its minimal value, specified by the pump location inside the wellbore.
In case this happens the well is switching to pressure control until the formation pressure and allow pump produce efficiently above minimal bottomhole pressure value.
Despite that many wells are operating under pressure control de facto they can be still simulated as under Liquid control assuming that their liquid rates have been manually pre-set adequately by Production technologist.
See also
Dynamic Flow Model (DFM) / Well control
[ Pressure Control ]