Thanks, glad it speaks to you! Right now it’s EPUB-only. That was my own need, and the whole thing is really built around book reading (reader, fonts, cross-device position sync, reading stats), so I focused on doing that one format well rather than handling everything.

CBZ/comics would need a different reader and a different idea of “reading position”, so it’s not on the roadmap for now. But if you give it a try, I’d love to hear how it goes.