Hi Simon, I'd be interested in your use case. Do you have some examples of what you call "proper localization with support for multiple languages and flexibility through additional config files"? I also work with asciidoctor so I'd be happy to see with them if upstream has that on their backlog.
To be honest, asciidoc hasn't been really active over the last few years (since its creator left the project) and even the current maintainers have advise several times to switch to asciidoctor (which has become the official reference for the asciidoc language), so the package does now support python3, yes, but I would still advise to look at alternatives long term. The reason I keep this one open for now is to make sure people realize that it's not because the language name is asciidoc that they should use the asciidoc binary. Joseph