The Debian packaging of git-annex is maintained in git, using the
merging workflow described in dgit-maint-merge(7).  There isn't a
patch queue that can be represented as a quilt series.

A detailed breakdown of the changes is available from their canonical
representation - git commits in the packaging repository.  For
example, to see the changes made by the Debian maintainer in the first
upload of upstream version 1.2.3, you could use:

    % git clone https://git.dgit.debian.org/git-annex
    % cd git-annex
    % git log --oneline 1.2.3..debian/1.2.3-1 -- . ':!debian'

(If you have dgit, use `dgit clone git-annex`, rather than plain `git
clone`.)

A single combined diff, containing all the changes, follows.
--- git-annex-10.20250416.orig/COPYRIGHT
+++ git-annex-10.20250416/COPYRIGHT
@@ -63,11 +63,14 @@ License: GPL-2
  The full text of version 2 of the GPL is distributed in
  /usr/share/common-licenses/GPL-2 on Debian systems.
 
+Files: Annex/DirHashes.hs
+Copyright: © 2010-2017 Joey Hess <id@joeyh.name>
+License: GPL-3+
+
 Files: Database/RawFilePath.hs
 Copyright: © 2012 Michael Snoyman, http://www.yesodweb.com/
            © 2023 Joey Hess <id@joeyh.name>
 License: Expat
- The text of the Expat license is in the Expat section below.
 
 Files: doc/tips/automatically_adding_metadata/pre-commit-annex 
 Copyright: 2014 Joey Hess <id@joeyh.name>
@@ -78,9 +81,6 @@ Files: static/jquery*
 Copyright: © 2005-2011 by John Resig, Branden Aaron & Jörn Zaefferer
            © 2011 The Dojo Foundation
 License: Expat or GPL-2
- The full text of version 2 of the GPL is distributed in
- /usr/share/common-licenses/GPL-2 on Debian systems. The text of the Expat
- license is in the Expat section below.
 
 Files: static/*/bootstrap* static/*/glyphicons-halflings*
 Copyright: 2012-2014 Twitter, Inc.
@@ -110,6 +110,10 @@ License: GPL-3+
  this package's source, or in /usr/share/common-licenses/GPL-3 on
  Debian systems.
 
+License: GPL-2
+ The full text of version 2 of the GPL is distributed in
+ /usr/share/common-licenses/GPL-2 on Debian systems.
+
 License: BSD-2-clause
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
