Manual:$wgDjvuToXML

Details
Path of the djvutoxml executable. Enable this and $wgDjvuRenderer to enable djvu rendering.

This works like djvudump except much, much slower as of version 3.5. For now I recommend you use djvudump instead. The djvuxml output is probably more stable, so we'll switch back to it as soon as they fix the efficiency problem.