Hmm...  Looks like a unified diff to me...
The text leading up to this was:
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|Author: Jan Christoph Ebersbach <jceb@e-jc.de>
|URL: http://dwm.suckless.org/patches/zoomswap
|This patch swaps the current window with the previous master when zooming.
|
|diff -r ec4baab78314 dwm.c
|--- a/dwm.c	Mon Dec 19 15:38:30 2011 +0100
|+++ b/dwm.c	Fri Apr 06 08:23:45 2012 +0200
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Patching file dwm.c using Plan A...
Hunk #1 succeeded at 253.
Hunk #2 succeeded at 2117.
done