Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|From 8f662e7a556f94bda83ec724fb036e15b2badaac Mon Sep 17 00:00:00 2001
|From: Jack Bird <jack.bird@durham.ac.uk>
|Date: Fri, 27 Aug 2021 01:14:44 +0100
|Subject: [PATCH] 6.2 focusmaster return
|
|---
| dwm.c | 39 +++++++++++++++++++++++++++++++++++++++
| 1 file changed, 39 insertions(+)
|
|diff --git a/dwm.c b/dwm.c
|index 4465af1..5219cbd 100644
|--- a/dwm.c
|+++ b/dwm.c
--------------------------
Patching file dwm.c using Plan A...
Hunk #1 succeeded at 127.
Hunk #2 succeeded at 168.
Hunk #3 succeeded at 661.
Hunk #4 succeeded at 821.
Hunk #5 succeeded at 1236.
Hmm...  Ignoring the trailing garbage.
done