Rated 3 out of 5 stars

It's not compatible with Thunderbird 76

This review is for a previous version of the add-on (2.1.6).  This user has a previous review of this add-on.

That's true - and it will not be necessary to have Enigmail in future versions of Thunderbird:

https://blog.thunderbird.net/2019/10/thunderbird-enigmail-and-openpgp/