A cool-down lapWhen a driver is on track but driving at a slower pace to cool the car down. Usually on the... There's more... done at lowish speeds, with minimal braking, allowing the heat in the discs and pads to dissipate.
Similarly for the engine, a gentle lap will allow the cooling system to lose some of the built-up heat from hard driving to cool down and the oil temp to drop.
They’ll still be hot when the car arrives back at its garageAn F1 garage is just that. A secure area for teams to set up their equipment and work on their... There's more..., but not excessively so.