The latest version of WMD on derobin's GitHub page is quite old and seems to be unmaintained. Following the social graph, the OpenLibrary WMD page looks much newer but still isn't the newest. Where is the authoritative source or blog or website? So I can follow development and discussions?
Found this post over on stackmeta: https://meta.stackexchange.com/questions/35084/is-there-an-official-stackoverflow-version-of-wmd-editor-available-for-download