Hi~ I found some documentation and video about this.
First, in the awknowledgments document, we do call it out: 'This product includes lua-nginx-module by OpenResty under the BSD license Copyright © 2009-2019 Yichun Zhang, Copyright © 2009-2017 Xiaozhe Wang, OpenResty. This product includes lua-resty-core module by OpenResty software under the BSD license Copyright © 2013-2019 Yichun Zhang.'
This is about the Lua module: https://docs.nginx.com/nginx/admin-guide/dynamic-modules/lua/
And, this is a video about Tracing and Troubleshooting NGINX, OpenResty, and Their Backends - https://youtu.be/NR8U1qYHGqk
Hope that helps!