So I just tried to download your documentation for python 3 by your epub link. I don't know how you generate your epub but you might want to review it, it seems to take an inordinate amount of time to load up on my devices (specifically in Okular on Linux, and Librera on Android). Once it does it works fine, but in the time that it took I'd came to think something had gone wrong. I'll probably just use another format for now.