TSL/Node hierarchy

I am currently developing a node editing website similar to the TSL-GRAPH website to learn about TSL and Node knowledge and to practice coding skills. However, I have encountered some issues: How is the node tree, or the hierarchical data, on the left sidebar of the website obtained? Has the official team published similar hierarchical data? Or is it static data that the website author has hardcoded into the webpage? I welcome everyone to discuss this. Thank you.

It is hardcoded.