JMOL is a set of applications that illustrate chemicals The software is open source, there is an extension for MediaWiki and it is not used in any of the Wikipedias.
The problem was that security issues were found with the software, further developments happened and then nothing. Recently, the subject of JMOL was raised again. The software had stopped working against the "bleeding edge" of MediaWiki, this has now been fixed.
Only one question is left. Now what ?