It's entirely custom but it leverages the d3 library so it's quite short/relatively simple in its execution as it leaves most of it up to d3. Process for findi

It's entirely custom but it leverages the d3 library so it's quite short/relatively simple in its execution as it leaves most of it up to d3. Process for finding out is not fixed. Generally a simple "View Source", look at <script> tags, read script files and look for obvious clues is the best first port of call (and worked easily here). If there's a lot of indirection and pre-compilation being done it gets harder.