More details about it, and how it can be used, are in the samples here:
https://github.com/microsoft/Analysis-Services/tree/master/ASJobGraphEvents
The data returned by the Job Graph event isn’t intelligible if you look at the text it returns in Profiler. However if you save a .trc file with Job Graph event data to XML you can use the Python scripts in the GitHub repo to generate DGML diagrams that can be viewed in Visual Studio, plus Gantt charts embedded in HTML. Of course to do this you’ll need to have Python installed; you’ll also need to have Visual Studio and its DGML editor installed (see here for details).
Read on to see how it looks and Chris’s thoughts on the matter.