Is there a config editor option to disable automatically attaching my public OpenPGP key (Options → Attach My Public Key) in Thunderbird 78 (which embedded Enigmail addon functionality into the email program)?
Currently, the Option to attach your public key can only be toggled on a per-mail basis and is set to on by default.
There is an issue on bugzilla, but currently there is no fix and I don't have any information if/when this feature will be added.
Update:
there is now an option to configure this in the config editor, for details look at: https://bugzilla.mozilla.org/show_bug.cgi?id=1654950#c55