From: Sender Example <sender@example.com>
To: Test Inbox <test@example.com>
Subject: Multipart alternative
Message-ID: <multipart-alternative-fixture@example.com>
Date: Tue, 30 Jun 2026 14:00:00 +0000
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="boundary-alt"

--boundary-alt
Content-Type: text/plain; charset=utf-8

Plain part of multipart alternative.

--boundary-alt
Content-Type: text/html; charset=utf-8

<html><body><p>HTML part of multipart alternative.</p></body></html>

--boundary-alt--