Rated 2 out of 5 stars

Sorry, but this plugins seems to guess TLS connections to be active.
I checked my actual/ old emails with faces (which are hard to differentiate) and their popup information and many emails without TLS notification in headers between mail servers were still marked as "Perfect - no known email providers and encryption between all hops" ???
Like this not too old email where you can yourself also subscribe/verify this behavior:

Received: from mail7.atl51.rsgsv.net ([205.201.135.7]) by mx-ha.gmx.net
(mxgmx011 [212.227.15.9]) with ESMTP (Nemesis) id 0LzGiX-1ffutS1fov-014QEI
for <[email protected]>; Wed, 10 Oct 2018 21:14:15 +0200
Received: from mail7.atl51.rsgsv.net ([205.201.135.7]) by mx-ha.gmx.net
(mxgmx011 [212.227.15.9]) with ESMTP (Nemesis) id 0LzGiX-1ffutS1fov-014QEI
for <[email protected]>; Wed, 10 Oct 2018 21:14:15 +0200
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; s=k1; d=divx.com;
h=Subject:From:Reply-To:To:Date:Message-ID:List-ID:List-Unsubscribe:
Content-Type:MIME-Version; [email protected];
bh=hKFncKmjznI7eWjYuebk14QtFUlkgSq0GCHGsM0zGWo=;
b=vr0HxyIJQVxudic78n62DFvEHXSnDXTtCKKYj8/EnmybQU5DhkVSqAh6hFiYL41LBM3LyRM219E1
4DrO4kVNxGqThmurSW1dmNvbW2rCMRMJm38l/rVeyfrHAuyD2pteJfeihRsmi0U9cfSFQYaubAQT
g2hcJZGQOMPq2HeYEEI=
Received: from (127.0.0.1) by mail7.atl51.rsgsv.net id hnp7oe2ddl4t for <[email protected]>; Wed, 10 Oct 2018 17:08:37 +0000 (envelope-from <[email protected]>)
Subject: =?utf-8?Q?Thank=20you=20=2D=2D=20get=2025%=20off=20DivX=20Pro=21=C2=A0?=
From: =?utf-8?Q?DivX=20News?= <[email protected]>
Reply-To: =?utf-8?Q?DivX=20News?= <[email protected]>


=> ESMTP usage isn't ESMTPS (or some TLS written headers)
=> DKIM signature is no encryption - only origin proove !


EDIT:/Answer - yes, sorry forgot to write it initially:
latest Thunderbird: 60.4.0 running with Windows 10 - latest version

This review is for a previous version of the add-on (0.2.7). 

It looks like it didn't detect any Received: headers. Even if somehow it was fooled by ESMTP, it would at least recognize gmx.net as a known provider.

Would you mind sharing your Tunderbird version and OS in the issue? https://github.com/gjedeer/paranoia/issues/24