I'm working through the tutorial on the WSIWYG official webapp now. The syntax for equations is remarkably intuitive! I tried a few things from guessing after skimming the tutorial, and they mostly worked in the most intuitive way. Here is what I gather this is. A mix of:
- Markdown general formatting (images, lists etc)
- LaTeX or MathJax-like equation syntax
- A rendering engine and software that turns these into pixels
