Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|From 653c99b94cc780a2def9c7e50a87703156535f8b Mon Sep 17 00:00:00 2001
|From: Jack Bird <jack.bird@durham.ac.uk>
|Date: Mon, 2 Aug 2021 18:50:02 +0100
|Subject: [PATCH] bartabgroups updated to work with 138b405
|
|---
| config.def.h |  11 +++++
| dwm.c        | 112 ++++++++++++++++++++++++++++++++++++++++++++++-----
| 2 files changed, 112 insertions(+), 11 deletions(-)
|
|diff --git a/config.def.h b/config.def.h
|index a2ac963..82accf1 100644
|--- a/config.def.h
|+++ b/config.def.h
--------------------------
Patching file config.def.h using Plan A...
Hunk #1 succeeded at 16.
Hunk #2 succeeded at 39.
Hmm...  The next patch looks like a unified diff to me...
The text leading up to this was:
--------------------------
|diff --git a/dwm.c b/dwm.c
|index 5e4d494..1839a56 100644
|--- a/dwm.c
|+++ b/dwm.c
--------------------------
Patching file dwm.c using Plan A...
Hunk #1 succeeded at 59.
Hunk #2 succeeded at 378.
Hunk #3 succeeded at 534.
Hunk #4 succeeded at 821.
Hmm...  Ignoring the trailing garbage.
done