SoGLColorIndexElement(3) on Linux
The text c4bf00dade20, as Debian 8 (Jessie) shipped it.
The SoGLColorIndexElement class sets the current OpenGL color. This element is only used when the OpenGL canvas is in colorindex mode, ie where colors for individual pixels are fetched from a color lookup table ('CLUT'). The usual thing to do is to set up a canvas in RGBA truecolor mode.