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 it is recommended that you use djvudump instead. The djvuxml output is probably more stable, so this recommendation may be reversed once they fix the efficiency problem.