SoGLLineWidthElement(3) on Linux
The text 0e1d35bba347, as Debian 4.0 (Etch) shipped it.
The SoGLLineWidthElement class changes the linewidth setting of the OpenGL render state. Requests from the scenegraph to change the linewidth when rendering OpenGL line primitives will be made through this element, which forwards it to the appropriate native OpenGL call.