Support for single-/multi- page DjVu documents
Since the introduction of the image/vnd.djvu+multipage mime-type, evince no longer opens single-page DjVu documents (image/vnd.djvu), but multi-page ones (image/vnd.djvu+multipage). As stated in the provided link
image/vnd.djvu could be an image, or a multi-page document. To avoid evince trying to use images (and for them to be shown as such in nautilus), I've added the image/vnd.djvu+multipage mime-type with the appropriate magic.
A priori, a single-page DjVu document could easily be, precisely that, a single-page document and not an image/picture, which makes the whole introduction of the multi-page mime-type confusing, at best. To make things worst, Eye-of-Gnome (Gnome's image viewer) won't open single-page DjVu documents, so the Gnome user is left with no solution for such files.
To make things even worst, some distribution have packages that create a conflict by overwriting the multi-page mime-type with the single-page one (
djvulibre in Fedora or
djvulibre-desktop in Ubuntu). A workaround is to uninstall such packages or to delete the file
/usr/share/mime/packages/djvulibre-mime.xml that they install.
Evince should be able to open single-page DjVu documents as most of such are in fact single-page documents and not pictures. I attach a handwritten document for testing purposes: t3cft01.djvu.