In 2002, the DjVu file format was chosen by the Internet Archive as a format in which its Million Book Project provides scanned public domain books online (along with TIFF and PDF).[8]

Fair enough but the main usage of my ePub files is reading them on an e-ink device. DjVu isn't an alternative to ePub then.

It is a bit questionable to have netbsd in there since it isn't that bad, but I would assume the rationale is "it is more complex than openbsd".