To: recipient@example.invalid
From: sender@example.invalid
Subject: Plaintext quoted-printable body ending on a soft line break
Message-ID: <qp-trailing-equals-plain@example.invalid>
Date: Mon, 6 Jul 2026 06:06:06 +0000
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable

This message body ends on a quoted-printable soft line break.
The needle qptrailingplain sits on the final line=