Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|From 3e020d93df3aaec92d2daa142cd1f0d5301b3197 Mon Sep 17 00:00:00 2001
|From: Mateus Auler <mateusauler@protonmail.com>
|Date: Fri, 17 Jul 2020 12:36:36 -0300
|Subject: [PATCH] Ability to map a key combination to switch focus to
| the master window.
|
|---
| dwm.c | 16 ++++++++++++++++
| 1 file changed, 16 insertions(+)
|
|diff --git a/dwm.c b/dwm.c
|index 9fd0286..be01927 100644
|--- a/dwm.c
|+++ b/dwm.c
--------------------------
Patching file dwm.c using Plan A...
Hunk #1 succeeded at 235.
Hunk #2 succeeded at 2152.
Hmm...  Ignoring the trailing garbage.
done