Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|diff '--color=auto' -up ../dmenu-4.9/dmenu.c ./dmenu.c
|--- ../dmenu-4.9/dmenu.c	2019-02-02 13:55:02.000000000 +0100
|+++ ./dmenu.c	2020-05-24 00:27:58.038586112 +0200
--------------------------
Patching file dmenu.c using Plan A...
Hunk #1 succeeded at 15.
Hunk #2 succeeded at 54.
Hunk #3 succeeded at 601.
Hunk #4 succeeded at 697.
Hunk #5 succeeded at 760.
Hunk #6 succeeded at 788.
done