Kinda, it looks like they add a bit of CSS (basically make everything monospaced & pre) so the Markdown text is visible when JS is disabled (noscript), but in a CSS-less browser (e.g. links) the file is received as HTML, and the Markdown code is directly interpreted as HTML, which makes for an unreadable mess (the whole thing is a single "line" with newlines collapsed to spaces)
You're really better off using a static conversion tool, or using markdeep as a static conversion tool (with ?export)
Or being greeted with a white page period if you're using a non-JS enabled HTML client (noscript, CLI browser).