javascript:document.body.appendChild(document.querySelector("#readme"));document.querySelector("header").remove();document.querySelector(".application-main").remove();document.querySelector("footer").remove();window.print();
Make it into a bookmarklet. It removes everything around the markdown article and opens the print dialog.
This is very nice, but only the first message in the thread is displayed with this snippet. Is that the intended behavior, @thomasverleye ?