This information is part of the Modelica Standard Library maintained by the Modelica Association.
This package contains functions to operate on colors. Note, a color is represented as a Real array with 3 elements where the elements are the red, green, blue values of the RGB color model. Every element must be in the range 0..255. The type of a color is Real and not Integer in order that a color can be used with less problems in a model, since in a model an Integer type could only be used in a when-clause. Typical declaration of a color value:
Real color(each min=0, each max=255);
This definition is also available as type Modelica.Mechanics.MultiBody.Types.RealColor.