Rated 5 out of 5 stars
I've been using this add-on for more than five years. Even with the slightly reduced functionality in Thunderbird 78, this is still an ESSENTIAL add-on. It enables Thunderbird to be used as as email *manager* rather than just an email writer-reader. Hopefully the developer will lobby Mozilla to enhance MailExtensions to allow showing tags in the toolbar. Personally I use five tags: Reply, Read, Action, Urgent, Info. I don't use all the functionality of the add-on (such as Categories) but I love the part that I do use.