Hi! Necroposting here, but... I wonder if someone has created a Git repository with this plugin, and, if so, where is it, and are you open to push/merge requests?
I've got the 'last' official version posted by @sunshineangel above, and sort of gave it a thorough cleaning up so that it runs under Calibre 6.29, but I'm afraid it's not 100% operational. Bear with me, I'm not a Python programmer at all, much less one who is familiar with how Calibre actually works...
At least, it won't crash Calibre
On the other hand, unfortunately, 6.29 is the last version I can run on my Mac. I guess I could download 7.25 and compile it from scratch, but I'm too lazy for that
