Nice!

It also does some niceties around fonts when you do a conversion. Some ebook readers dont come with specific fonts so they just use the inbuilt one(s).

Just FYI, older Kobos are exceptionally easy to repair and modify. They used to have an SD card as the hd you could remove and do all sorts of cool things with. They also published the version of the linux kernel they used and any modifications they (Kobo) devs had to do to get things working. It was awesome for a time. Its more locked down now… :(

I used to play around with https://quill-os.org/ and it worked decently well on kobo until the newer versions started to crack down on the mod scene.

Nowadays im thinking the open book or Diptyx E-Reader might be a better bet for long term sustainability. Its great ifixit is working with kobo, but the software is still locked down.

For a bigger list take a look: https://itsfoss.com/open-source-ebook-readers-options/