what is the first line of git format-patch output?

From git help format-patch

DISCUSSION
The patch produced by git format-patch is in UNIX mailbox format, with
a fixed “magic” time stamp to indicate that the file is output from
format-patch rather than a real mailbox, like so:

       From 8f72bad1baf19a53459661343e21d6491c3908d3 Mon Sep 17 00:00:00 2001
       From: Tony Luck <tony.luck@intel.com>
       Date: Tue, 13 Jul 2010 11:42:54 -0700
       Subject: [PATCH] =?UTF-8?q?> > [IA64]=20Put=20ia64=20config=20files=20on=20the=20?=
        =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20diet?=
       MIME-Version: 1.0
       Content-Type: text/plain; charset=UTF-8
       Content-Transfer-Encoding: 8bit