Rated 5 out of 5 stars

Great tool. Epub as an archive format for web pages and emails (rather than PDF or MHT). I hope it will be updated soon for Thunderbird 60. Thank you!

This review is for a previous version of the add-on (0.6). 

Hello Firstfox,
I am the maintainer of the extension. I thank you for your nice review.
I started migrating the extension to Thunderbird 60. It seems that there are a couple of issues to fix but I hope that I can update it soon.