I don't have one of those levers, but I have vents that allow the air con to cool the inside of the centre console. Someone mentioned they could open and close their vents with a lever. Could that be it?
2003 W209 CLK, 2005 R171 SLK, Volvo XC40 P8 Twin Motor Pro EV
It opens and closes the air vents in the box. I forget which way opens the vents as I never use it on ours but basically it turns it into a coolbox when the aircon is running.