What in all actually is this PDF attachment doing with the newsletter?
I'm fairly confident that this also came from Stack Exchange, so would someone care to enlighten me as to what's going on? I admit I'm rusty at reading mail headers, but the sources seem to line up just fine.
Delivered-To: --REDACTED-- Received: by 10.229.68.6 with SMTP id t6csp224071qci; Fri, 20 Mar 2015 12:28:47 -0700 (PDT) X-Received: by 10.55.31.97 with SMTP id f94mr119580342qkf.10.1426879727323; Fri, 20 Mar 2015 12:28:47 -0700 (PDT) Return-Path: <firstname.lastname@example.org> Received: from mx-out.stackexchange.com (mx-out.stackexchange.com. [18.104.22.168]) by mx.google.com with ESMTPS id i90si5136899qge.83.2015.03.20.12.28.46 for <--REDACTED--> (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 20 Mar 2015 12:28:47 -0700 (PDT) Received-SPF: pass (google.com: domain of email@example.com designates 22.214.171.124 as permitted sender) client-ip=126.96.36.199; Authentication-Results: mx.google.com; spf=pass (google.com: domain of firstname.lastname@example.org designates 188.8.131.52 as permitted sender) email@example.com; dkim=pass firstname.lastname@example.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=stackexchange.com; s=dk; h=Content-Type:Message-ID:Date:Subject:Reply-To:To:From:MIME-Version; bh=1OWPTURI/S9xuD+By0vS6qm84rNbZTEnVTBe0n3jV2Q=; b=VEwIjIH/yuaj1DiAJMIuXOs8vPo1fhJOHhM7v9IWtvRozVyDnMzZBeFVsaAiUDSmsMrXb8sH3X0TU2a94KkuzByGyong8s4pRn6CridgSwOJuQ1OLhN/zSNiSu00rPENBxFhmiABN0PNx8m6S8OZHwMMPob6SzQUm5IK1JsjFxY=; Received: from [10.7.2.15] (helo=[10.7.2.101]) by mx-out.stackexchange.com with esmtp (Exim 4.72) (envelope-from <email@example.com>) id 1YZ0VC-0006l0-SY for --REDACTED--; Fri, 20 Mar 2015 17:14:30 +0000 MIME-Version: 1.0 X-Mailer: MailBee.NET 184.108.40.2064 From: "Stack Exchange" <firstname.lastname@example.org> To: --REDACTED-- Reply-To: email@example.com Subject: Super User Weekly Newsletter - Friday, March 20, 2015 Date: Fri, 20 Mar 2015 17:14:30 +0000 Message-ID: <2.9e47a33dae2ecd6e7599@NY-WEB01> Content-Type: multipart/alternative;