SoNurbsCurve(3) on Linux
The text 6421fe55e81b, as Debian 7 (Wheezy) shipped it.
The SoNurbsCurve class is a node for representing smooth curves. A general explanation of NURBS is beyond the scope of the Coin documentation. For detailed information, refer to the specialized literature on the topic (for example 'An Introduction to NURBS: With Historical Perspective' by David F. Rogers). A basic overview of curve and surface rendering using NURBS can be found in chapter 8 of 'The Inventor Mentor'.