How does Glitch render

Just a technical question out of curiosity. How is a markdown file rendered on Glitch? In particular,

  1. Is Glitch using server-side or client-side rendering?
  2. Which library (or libraries) is it using? (both of renderer and styling)

For server-side tutorials/examples, a page generated from could be a nice index.html, which would be best if it appears exactly the same as in the editor.

Digging into Chrome Devtools got me most of the answer (I think). Please correct me if something is wrong.