Arrow on car monitors
Usually, on the monitors of cars you can find a little arrow on one of the sides next to the gasoline indicator, more specifically in cars created in 2010 onwards. And as far as is known, these arrows, which can show to the left or right, are used to indicate in which direction the gas cap is placed.
Although this may not be so useful if you have been driving the same car for a long time. But it may be useful when the car is new or rented.