https://news.ycombinator.com/item?id=11444122
https://news.ycombinator.com/item?id=11448908
What is interesting is that they will apparently be releasing their work as open source:
"With that said, as far as we are concerned, this amazing journey would not have been possible without the contribution of the open source World of Warcraft community, especially those who were behind MaNGOS. We believe that we significantly improved their code base, with several interesting algorithms (for example the ongoing work on clustering). For now, our source code may be release 30th of April (educational purposes only) in the hope that it will be useful, and that it may help developers understand how a big project like ours was handled from the inside."
(from https://forum.nostalrius.org/viewtopic.php?f=2&t=43600)