The Color setting only applies to exports where the Background Type is set to Ray Cube. The color chosen here will become the solid background color in your scene. This setting corresponds to the Primary Shader setting of a Ray Cube in the Render Scene Environment Editor.
The images below demonstrate the effects of changing the Color setting from Black to a Green color.
The example images were rendered from the Isometric_SW view using the "Stark" Cubical Map and "Quality" Luminance presets.
Color = Black
Color = Green
You may have noticed that even though the background in the second image has turned green, the reflections in the pot have not changed. This is not an error, but one of the great reasons for choosing to use a Ray Cube. A Ray Cube gives you control of the reflections and refraction in your scene independently of what's taking place with the background. They are controlled by the Reflected Shader and the Refracted Shader settings of the Ray Cube.
The images below show the results of further adjustment to a Ray Cube in the Render Scene Environment Editor. In the first image, the Reflected Shader has been set to the same Green color that is used in the background. In the second image, the Reflected Shader is set to Mixed which allows two Reflected Shader settings to be mixed by percentage. The two chosen are the same Green color and Environment. The Environment setting adds our umbrella back to the image.