diff --git a/CHANGELOG b/CHANGELOG
index 8e8a0afb2b..bd46e47235 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -6,6 +6,9 @@ git-annex (10.20221004) UNRELEASED; urgency=medium
     do not operate on a repository that has an empty name.
   * move: Fix openFile crash with -J
     (Fixes a reversion in 8.20201103)
+  * S3: Support signature=anonymous to access a S3 bucket anonymously.
+    This can be used, for example, with importtree=yes to import from
+    a public bucket.
 
  -- Joey Hess <id@joeyh.name>  Mon, 03 Oct 2022 13:36:42 -0400
 
diff --git a/Remote/S3.hs b/Remote/S3.hs
index 1f0ebd3d5a..c0d99b5418 100644
--- a/Remote/S3.hs
+++ b/Remote/S3.hs
@@ -1,6 +1,6 @@
 {- S3 remotes
  -
- - Copyright 2011-2020 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2022 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -156,7 +156,9 @@ requeststyleField = Accepted "requeststyle"
 signatureField :: RemoteConfigField
 signatureField = Accepted "signature"
 
-newtype SignatureVersion = SignatureVersion Int
+data SignatureVersion 
+	= SignatureVersion Int
+	| Anonymous
 
 signatureVersionParser :: RemoteConfigField -> FieldDesc -> RemoteConfigFieldParser
 signatureVersionParser f fd =
@@ -165,10 +167,17 @@ signatureVersionParser f fd =
   where
 	go "v2" = Just (SignatureVersion 2)
 	go "v4" = Just (SignatureVersion 4)
+	go "anonymous" = Just Anonymous
 	go _ = Nothing
 
 	defver = SignatureVersion 2
 
+isAnonymous :: ParsedRemoteConfig -> Bool
+isAnonymous c = 
+	case getRemoteConfigValue signatureField c of
+		Just Anonymous -> True
+		_ -> False
+
 portField :: RemoteConfigField
 portField = Accepted "port"
 
@@ -272,7 +281,9 @@ s3Setup'  ss u mcreds c gc
 		(c', encsetup) <- encryptionSetup (c `M.union` defaults) gc
 		pc <- either giveup return . parseRemoteConfig c'
 			=<< configParser remote c'
-		c'' <- setRemoteCredPair ss encsetup pc gc (AWS.creds u) mcreds
+		c'' <- if isAnonymous pc
+			then pure c'
+			else setRemoteCredPair ss encsetup pc gc (AWS.creds u) mcreds
 		pc' <- either giveup return . parseRemoteConfig c''
 			=<< configParser remote c''
 		info <- extractS3Info pc'
@@ -286,7 +297,9 @@ s3Setup'  ss u mcreds c gc
 		showNote "Internet Archive mode"
 		pc <- either giveup return . parseRemoteConfig c
 			=<< configParser remote c
-		c' <- setRemoteCredPair ss noEncryptionUsed pc gc (AWS.creds u) mcreds
+		c' <- if isAnonymous pc
+			then pure c
+			else setRemoteCredPair ss noEncryptionUsed pc gc (AWS.creds u) mcreds
 		-- Ensure user enters a valid bucket name, since
 		-- this determines the name of the archive.org item.
 		let validbucket = replace " " "-" $ map toLower $
@@ -841,17 +854,20 @@ type S3HandleVar = TVar (Either (Annex (Maybe S3Handle)) (Maybe S3Handle))
 {- Prepares a S3Handle for later use. Does not connect to S3 or do anything
  - else expensive. -}
 mkS3HandleVar :: ParsedRemoteConfig -> RemoteGitConfig -> UUID -> Annex S3HandleVar
-mkS3HandleVar c gc u = liftIO $ newTVarIO $ Left $ do
-	mcreds <- getRemoteCredPair c gc (AWS.creds u)
-	case mcreds of
-		Just creds -> do
-			awscreds <- liftIO $ genCredentials creds
-			let awscfg = AWS.Configuration AWS.Timestamp awscreds debugMapper Nothing
-			ou <- getUrlOptions
-			return $ Just $ S3Handle (httpManager ou) awscfg s3cfg
-		Nothing -> return Nothing
+mkS3HandleVar c gc u = liftIO $ newTVarIO $ Left $
+	if isAnonymous c
+		then go =<< liftIO AWS.anonymousCredentials
+		else do
+			mcreds <- getRemoteCredPair c gc (AWS.creds u)
+			case mcreds of
+				Just creds -> go =<< liftIO (genCredentials creds)
+				Nothing -> return Nothing
   where
 	s3cfg = s3Configuration c
+	go awscreds = do
+		let awscfg = AWS.Configuration AWS.Timestamp awscreds debugMapper Nothing
+		ou <- getUrlOptions
+		return $ Just $ S3Handle (httpManager ou) awscfg s3cfg
 
 withS3Handle :: S3HandleVar -> (Maybe S3Handle -> Annex a) -> Annex a
 withS3Handle hv a = liftIO (readTVarIO hv) >>= \case
diff --git a/doc/special_remotes/S3.mdwn b/doc/special_remotes/S3.mdwn
index e34cbb7f9d..5bda70f98a 100644
--- a/doc/special_remotes/S3.mdwn
+++ b/doc/special_remotes/S3.mdwn
@@ -82,6 +82,7 @@ the S3 remote.
 * `signature` - This controls the S3 signature version to use.
   "v2" is currently the default, "v4" is needed to use some S3 services.
   If you get some kind of authentication error, try "v4".
+  To access a S3 bucket anonymously, use "anonymous".
 
 * `bucket` - S3 requires that buckets have a globally unique name, 
   so by default, a bucket name is chosen based on the remote name
diff --git a/stack.yaml b/stack.yaml
index 7dbfb657ac..988296933b 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -11,10 +11,10 @@ flags:
     gitlfs: true
 packages:
 - '.'
-resolver: lts-18.13
+resolver: lts-19.16
 extra-deps:
 - IfElse-0.85
-- aws-0.22
+- /home/joey/tmp/aws
 - bloomfilter-2.0.1.0
 - git-lfs-1.2.0
 - http-client-restricted-0.0.4
@@ -24,4 +24,3 @@ extra-deps:
 - base16-bytestring-0.1.1.7
 - base64-bytestring-1.0.0.3
 - bencode-0.6.1.1
-- http-client-0.7.9