Thunderbird 78 comes with a completely revamped OpenPGP integration. Several features get implemented over the course of time, but might need manual configuration. In this article, I show you how to avoid attaching your public OpenPGP key to each encrypted e-mail you send.
Currently, there is no user interface element to tweak this setting. In order to disable the feature, you need to open the Config Editor, which is in the mail client’s settings, on the first page at the bottom.
The Config Editor gives you access to a lot of options that are not visible from the user interface for a good reason. If you misconfigure things, you might make your Thunderbird installation unusable – so always keep a good backup in place and be careful what you do. Use the Config Editor at your own risk!
Depending on how many e-mail accounts you have setup, in the Config Editor, search for the settings
mail.identity.default.attachPgpKey mail.identity.id1.attachPgpKey mail.identity.id2.attachPgpKey
etc. and set all of these to false. In case the respective settings do not exist, you can also create them as type boolean from within the Config Editor.
Your OpenPGP key will not be automatically added to outgoing e-mails anymore.