Vents in boot area

[Alfredo]

Can someone please tell me what the 2 vents are for in the boot area of the RX400h?

[NemesisUK]

Traction Battery ventilation?

[Britprius]

Most cars have these hidden away somewhere. They are there for two reasons. When the heater or AC is on drawing air from outside the air in the cabin would have to be compressed unless some air was vented. The air in the cabin has to be vented to make way for the fresh air.
The other reason "more noticeable in older cars without the feature" is that it enables easy closing of doors. If say only the drivers door is open and you try to shut it the air in the car is compressed particularly if the door is slammed or closed quickly. This can prevent the door closing completely.

The vents have a one way flap valve that prevents airflow in the reverse direction. This also helps keep the car from flooding if driven through deep water.

John.