Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|URL: http://dwm.suckless.org/patches/gapless_grid
|Add gapless grid layout.
|
|Index: dwm/gaplessgrid.c
|===================================================================
|--- /dev/null
|+++ dwm/gaplessgrid.c
--------------------------
(Creating file gaplessgrid.c...)
Patching file gaplessgrid.c using Plan A...
Empty context always matches.
Hunk #1 succeeded at 1.
done