JointJS exports three global variables, the `joint` namespace, the `V` variable and the `g` variable (that is described later in the Geometry section). The `V` variable is a function of a little SVG helper library that we call Vectorizer. The reason why this library sits in its own namespace and not inside the `joint` namespace is that it can be used completely standalone, even without JointJS. It is a very helpful library making life easier when dealing with SVG. You can think of it as of a very lightweight jQuery for SVG. If you want to use Vectorizer as a standalone library, see the download page that contains both the development and minified versions.