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-8.20210223.orig/COPYRIGHT
+++ git-annex-8.20210223/COPYRIGHT
@@ -69,6 +69,10 @@ 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: doc/tips/automatically_adding_metadata/pre-commit-annex 
 Copyright: 2014 Joey Hess <id@joeyh.name>
            2016 Klaus Ethgen <Klaus@Ethgen.ch>
@@ -78,9 +82,6 @@ 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 +111,10 @@ 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
--- git-annex-8.20210223.orig/Git/Tree.hs
+++ git-annex-8.20210223/Git/Tree.hs
@@ -300,43 +300,43 @@ graftTree'
 	-> Repo
 	-> MkTreeHandle
 	-> IO Sha
-graftTree' subtree graftloc basetree repo hdl = go basetree graftdirs
+graftTree' subtree graftloc basetree repo hdl = go basetree subdirs graftdirs
   where
-	go tsha (topmostgraphdir:restgraphdirs) = do
+	go tsha (subdir:restsubdirs) (topmostgraphdir:restgraphdirs) = do
 		Tree t <- getTree LsTree.LsTreeNonRecursive tsha repo
-		t' <- case partition isabovegraft t of
+		let abovegraftpoint i = gitPath i == gitPath subdir
+		t' <- case partition abovegraftpoint t of
+			-- the graft point is not already in the tree,
+			-- so graft it in, keeping the existing tree
+			-- content
 			([], _) -> do
 				graft <- graftin (topmostgraphdir:restgraphdirs)
 				return (graft:t)
-			-- normally there can only be one matching item
-			-- in the tree, but it's theoretically possible
-			-- for a git tree to have multiple items with the
-			-- same name, so process them all
 			(matching, rest) -> do
 				newshas <- forM matching $ \case
 					RecordedSubTree tloc tsha' _
 						| null restgraphdirs -> return $
 							RecordedSubTree tloc subtree []
 						| otherwise -> do
-							tsha'' <- go tsha' restgraphdirs
+							tsha'' <- go tsha' restsubdirs restgraphdirs
 							return $ RecordedSubTree tloc tsha'' []
 					_ -> graftin (topmostgraphdir:restgraphdirs)
 				return (newshas ++ rest)
 		mkTree hdl t'
-	go _ [] = return subtree
-
-	isabovegraft i = beneathSubTree i graftloc || gitPath i == gitPath graftloc
+	go _ _ [] = return subtree
 	
 	graftin t = recordSubTree hdl $ graftin' t
 	graftin' [] = RecordedSubTree graftloc subtree []
 	graftin' (d:rest) 
 		| d == graftloc = graftin' []
 		| otherwise = NewSubTree d [graftin' rest]
-	
+
+	subdirs = splitDirectories $ gitPath graftloc
+
 	-- For a graftloc of "foo/bar/baz", this generates
 	-- ["foo", "foo/bar", "foo/bar/baz"]
 	graftdirs = map (asTopFilePath . toInternalGitPath . encodeBS) $
-		mkpaths [] $ splitDirectories $ gitPath graftloc
+		mkpaths [] subdirs
 	mkpaths _ [] = []
 	mkpaths base (d:rest) = (joinPath base </> d) : mkpaths (base ++ [d]) rest
 
--- git-annex-8.20210223.orig/git-annex.cabal
+++ git-annex-8.20210223/git-annex.cabal
@@ -322,7 +322,7 @@ Executable git-annex
    unix-compat (>= 0.5),
    SafeSemaphore,
    async,
-   directory (>= 1.2),
+   directory (>= 1.2.7.0),
    disk-free-space,
    filepath,
    filepath-bytestring (>= 1.4.2.1.1),
