How can I add metadata to a DjVu file?
$ exiftool sample.djvu | grep -P "^===|Title|Author" Title : Group Theory and Physics Author : Shlomo Sternberg
It sounds like XMP metadata would do the trick:
$ djvused sample.djvu -e 'set-xmp sample.xmp'
Though I'm unsure how to create the XMP file itself -- and examples on the internet are sparse.