Migrate from Enigmail to Thunderbird 78's built-in OpenPGP support
The next Thunderbird ESR after v68 will have its own OpenPGP support and Enigmail will go away:
- https://blog.mozilla.org/thunderbird/2019/10/thunderbird-enigmail-and-openpgp/
- https://wiki.mozilla.org/Thunderbird:OpenPGP:2020
Parent Task: #17148
Related issues
Original created by @intrigeri on 17147 (Redmine)