What does the triangle next to the petrol indicator in the car’s cabin symbolize?

Many people know that the fuel indicator in the dashboard determines the level of gasoline in the car’s fuel tank, which determines whether the car needs fuel or not before reaching the danger stage, which is when the fuel runs out.
But not many know the meaning of the arrow next to the fuel sign in the fuel indicator and what it indicates, and most people do not even know its existence.
This triangle indicates the location of the fuel tank door, where the commander indicates where to place the fuel pistol to fill the tank so that the commander does not get confused every time he needs to fill the fuel if the door is on the right or the left.
As there are cars, the door is to the right, so the direction of the triangle is to the right, and some other cars have the tank door to the left, so the direction of the triangle is to the left.
Bearing in mind that there are cars that do not have this triangle in the dashboard, and the leg must know the location of the tank door to fill the fuel itself.