Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|Only in .: config.h
|diff -up ../dmenu-5.0/dmenu.c ./dmenu.c
|--- ../dmenu-5.0/dmenu.c	Wed Sep  2 18:37:07 2020
|+++ ./dmenu.c	Wed Nov  4 15:25:27 2020
--------------------------
Patching file dmenu.c using Plan A...
Hunk #1 succeeded at 501.
Hunk #2 succeeded at 711.
Hunk #3 succeeded at 814.
done