Where is the image effect graph?

I have seen the image effect graph or “Image Effect Master Output” but for some reason I cannot find this, am I doing something wrong or has this feature been removed?

This blog shows it being used: https://unitylist.com/p/hjl/Image-Effect-Graph

For clarification I am using Unity 2018.0.3.0f2, I have the Lightweight Render Pipeline and I believe I have the necessary packages installed.

It was never an official Unity thing. A user created it by extending the Shader Graph:

Thanks for the response, I thought Unity had made this and changed it to the Visual Effect Graph or something.