I'm not sure it's markdown specifically, seems to be a homegrown markup language, made by Joe himself. Here is the "renderer" part of the website: https://joear

I'm not sure it's markdown specifically, seems to be a homegrown markup language, made by Joe himself. Here is the "renderer" part of the website: https://joearms.github.io/src/expander.js https://joearms.github.io/src/expander.js > expander.js - a markup parser > Hopefully the last JS I every write > Very few regular expressions were used in the construction of this program > No libraries were were used in the construction of this program > All faults are mine and mine alone > Appears to work :-) Points to https://github.com/joearms/bookmaker https://github.com/joearms/bookmaker which doesn't seem to exist anymore.