Bring this Addon to Thunderbird Itself

[yoshimo]

DKIM has been asked for upstream more than 16years ago in https://bugzilla.mozilla.org/show_bug.cgi?id=265226
With all the spam and phishing mails impersonating legitimate domains it has become difficult to sort incoming mails properly.
If you sort by domain, the forged mails get into the wrong folder.
Being able to verify the DKIM and ARC headers would be great here.
Also lessens the burden of maintenance for new TB releases.
I hope you can consider bringing the code for this into proper shape for merging and solving this ancient bug.

[lieser]

I currently don't see myself finding the motivation/time for working on integrating this directly into Thunderbird. Besides the currently ongoing porting to WebExtension, the maintenance effort for new Thunderbird versions was also rather low.

And both client side DKIM verification (server breaking DKIM, like Outlook) and using of the ARH header (how to ensure it is trustworthy, like discussed in the bug you linked) can have some problems. So I'm unsure if the Thunderbird developers would consider this feature important/relevant enough for integration.

Of course, if others are willing to work on this, feel free to reuse the code from the add-on. I'm definitely not against Thunderbird getting DKIM support out of the box.