Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|From 36c4e246ad47333f2b8a82610ba2adebeb2043b2 Mon Sep 17 00:00:00 2001
|From: Jack Bird <jack.bird@durham.ac.uk>
|Date: Thu, 29 Jul 2021 21:39:33 +0100
|Subject: [PATCH] Able to switch to master from anywhere in the stack and can
| also return to the previously selected client from the master
|
|---
| dwm.c | 28 ++++++++++++++++++++++++++++
| 1 file changed, 28 insertions(+)
|
|diff --git a/dwm.c b/dwm.c
|index 5e4d494..eab8d57 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 662.
Hunk #4 succeeded at 821.
Hunk #5 succeeded at 1230.
Hmm...  Ignoring the trailing garbage.
done