For some reason, I was curious to know if there were any utilities to convert PDF to FXL ePub. Calibre does not support it. I found a shell script that orchestrated a conversion using Poppet and ImageMagick, but no thanks, too much.
Then I realized KFX Input would convert from Print Replica to ePub. And yes, you can convert PDF --> Print Replica with Send to Kindle and from there to ePub FXL
with the plugin. It looks fine!
But: FXL is a poor stand in for PDF, functionally. E.g., you cannot select or highlight text. So Comics, children's books maybe. But not textbooks or that sort of thing (KF8 fixed layout is the same). And not accessible to screen readers. There's a W3 draft spec to address this:
Still, there may be use cases for it. I wonder if it is possible to tweak the plugin to take PDF directly and convert to ePub?