The M2Eclipse website is a Jekyll-based website that is primarily written in the Markdown format, with a bit of plain HTML.
You can use any Markdown editor for the developer-centric pages (*.md), and all normal Jekyll commands will work to build/render the site.
You can also use the script provided to run the Java implementation of Jekyll if you don't want to install Ruby/Jekyll on your system.
./jekyll.sh
Now you can go to http://localhost:4000/m2e/ to see the site.