The bilinual Project also rebuild ebooks (modern HTML, PDF and open ePUB format) with better quality and readability( while it is not its prime goal). Take a look at one example here:
https://www.bilinual.com/book/18043sven/sv/en#line=68&lpp=23 https://www.bilinual.com/download/18043sven-sv-en.pdf https://www.bilinual.com/download/18043sven-sv-en.epub
https://dave.autonoma.ca/blog/2020/04/11/project-gutenberg-p...
fwiw, Gitenberg has been around at least since 2012.
The Girl from Alsace in Gitenberg: https://www.gitenberg.org/book/35926
The Girl from Alsace in Gutenberg: http://www.gutenberg.org/ebooks/35926
The numbers are even the same which seems suspicious. Hmmm.