What does this mean?

 

what you are showing is a normal information screen and not a warning. This is the "energy transfer" screen that shows whether energy is to or from the wheels, etc.

on your steering wheel, (right side?) you have an up/down button and you can cycle to a different screen if you'd like.

 

I bet you just bought this used vehicle! Welcome to the club of owners of the rare Lexus HS250h. Don't worry as it is the same engine and hybrid system as in the Toyota Camry, so mechanics know how to work on it and parts are easily available.
Warning lights appear on the screen as individual lights just like other vehicles.

What he said is correct. That is the normal display showing energy transfer between the gas motor, electric motor and the wheels etc.
The toggle switch on the right side of the steering wheel lets you move between different displays on that screen, including tire pressure, temperature, etc.
If you have navigation that screen too has deeper displays of hybrid functions etc that you can dig into if interested.