Yes. I should have been more clear. He is not against python3 but thinks that it is less work to maintain python2 than port calibre to newer version.

This sounds like Calibre codebase is a mess that needs to be refactored.

To be honest the best part of Calibre, the `ebook-convert` tool, is already broken out from the rest of it. It's similar to pandoc though in my opinion often does a nicer job.

Even the best codebase can't effortless be ported. Calibre seems to have something around 25 MB of python-code, several external plugins, some C-code and other languages. Transition of this would take quite some time.

Additionally, there is the problem of compability. Configuration in Calibre is python-code, and on several corners the user can mod stuff. Any transition would need to make sure to not brake things to hard.

Oh. Like every single codebase ever then?