Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|From b5d3351a21442a842e01e8c0317603b6890b379c Mon Sep 17 00:00:00 2001
|From: asparagii <michele.lambertucci1@gmail.com>
|Date: Thu, 27 Jan 2022 15:44:02 +0100
|Subject: [PATCH] st-scrollback-mouse
|
|---
| config.def.h | 2 ++
| 1 file changed, 2 insertions(+)
|
|diff --git a/config.def.h b/config.def.h
|index e3b469b..c217315 100644
|--- a/config.def.h
|+++ b/config.def.h
--------------------------
Patching file config.def.h using Plan A...
Hunk #1 succeeded at 176.
Hmm...  Ignoring the trailing garbage.
done