diff --git a/mercurial/changegroup.py b/mercurial/changegroup.py
--- a/mercurial/changegroup.py
+++ b/mercurial/changegroup.py
@@ -1468,7 +1468,7 @@
     needv03 = False
     if (
         repo.ui.configbool(b'experimental', b'changegroup3')
-        or repo.ui.configbool(b'experimental', b'treemanifest')
+        or repo.ui.configbool(b'storage', b'treemanifest')
         or b'treemanifest' in repo.requirements
     ):
         # we keep version 03 because we need to to exchange treemanifest data
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -679,9 +679,6 @@
     b'experimental', b'sparse-read.min-gap-size', default=b'65K',
 )
 coreconfigitem(
-    b'experimental', b'treemanifest', default=False,
-)
-coreconfigitem(
     b'experimental', b'update.atomic-file', default=False,
 )
 coreconfigitem(
@@ -1056,6 +1053,10 @@
     b'storage', b'revlog.zstd.level', default=None,
 )
 coreconfigitem(
+    b'storage', b'treemanifest', default=False,
+    alias=[(b'experimental', b'treemanifest')],
+)
+coreconfigitem(
     b'server', b'bookmarks-pushkey-compat', default=True,
 )
 coreconfigitem(
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -3515,7 +3515,7 @@
     # experimental config: format.use-side-data
     if ui.configbool(b'format', b'use-side-data'):
         requirements.add(SIDEDATA_REQUIREMENT)
-    if ui.configbool(b'experimental', b'treemanifest'):
+    if ui.configbool(b'storage', b'treemanifest'):
         requirements.add(b'treemanifest')
 
     revlogv2 = ui.config(b'experimental', b'revlogv2')
diff --git a/tests/test-narrow-clone-stream.t b/tests/test-narrow-clone-stream.t
--- a/tests/test-narrow-clone-stream.t
+++ b/tests/test-narrow-clone-stream.t
@@ -6,7 +6,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-narrow-commit.t b/tests/test-narrow-commit.t
--- a/tests/test-narrow-commit.t
+++ b/tests/test-narrow-commit.t
@@ -4,7 +4,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-narrow-merge.t b/tests/test-narrow-merge.t
--- a/tests/test-narrow-merge.t
+++ b/tests/test-narrow-merge.t
@@ -4,7 +4,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-narrow-share.t b/tests/test-narrow-share.t
--- a/tests/test-narrow-share.t
+++ b/tests/test-narrow-share.t
@@ -4,7 +4,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-narrow-sparse.t b/tests/test-narrow-sparse.t
--- a/tests/test-narrow-sparse.t
+++ b/tests/test-narrow-sparse.t
@@ -10,7 +10,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-narrow-strip.t b/tests/test-narrow-strip.t
--- a/tests/test-narrow-strip.t
+++ b/tests/test-narrow-strip.t
@@ -12,7 +12,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-narrow-trackedcmd.t b/tests/test-narrow-trackedcmd.t
--- a/tests/test-narrow-trackedcmd.t
+++ b/tests/test-narrow-trackedcmd.t
@@ -3,7 +3,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-narrow-widen-no-ellipsis.t b/tests/test-narrow-widen-no-ellipsis.t
--- a/tests/test-narrow-widen-no-ellipsis.t
+++ b/tests/test-narrow-widen-no-ellipsis.t
@@ -3,7 +3,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-narrow-widen.t b/tests/test-narrow-widen.t
--- a/tests/test-narrow-widen.t
+++ b/tests/test-narrow-widen.t
@@ -3,7 +3,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-narrow.t b/tests/test-narrow.t
--- a/tests/test-narrow.t
+++ b/tests/test-narrow.t
@@ -17,7 +17,7 @@
 
 #if tree
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
+  > [storage]
   > treemanifest = 1
   > EOF
 #endif
diff --git a/tests/test-strip-cross.t b/tests/test-strip-cross.t
--- a/tests/test-strip-cross.t
+++ b/tests/test-strip-cross.t
@@ -164,13 +164,13 @@
 
 Now a similar test for a non-root manifest revlog
   $ cat >> $HGRCPATH <<EOF
-  > [experimental]
+  > [storage]
   > treemanifests = yes
   > EOF
   $ mkdir treemanifests
   $ cd treemanifests
   $ 
-  $ hg --config experimental.treemanifest=True init orig
+  $ hg --config storage.treemanifest=True init orig
   $ cd orig
   $ commit 'dir/file'
   $ commit 'dir/other'
@@ -179,7 +179,7 @@
   $ commit 'otherdir dir/file'
   $ commit 'otherdir dir/other' 'otherdir dir/file'
   $ cd ..
-  $ hg --config experimental.treemanifest=True clone -q -U -r 1 -r 2 -r 3 -r 4 orig crossed
+  $ hg --config storage.treemanifest=True clone -q -U -r 1 -r 2 -r 3 -r 4 orig crossed
   $ cd crossed
   $ hg debugindex --dir dir
      rev linkrev nodeid       p1           p2
@@ -190,7 +190,7 @@
 
   $ cd ..
   $ for i in 2 3; do
-  >     hg --config experimental.treemanifest=True clone -q -U --pull crossed $i
+  >     hg --config storage.treemanifest=True clone -q -U --pull crossed $i
   >     echo "% Trying to strip revision $i"
   >     hg --cwd $i strip $i
   >     echo "% Verifying"
diff --git a/tests/test-treemanifest.t b/tests/test-treemanifest.t
--- a/tests/test-treemanifest.t
+++ b/tests/test-treemanifest.t
@@ -5,7 +5,7 @@
 
 Set up repo
 
-  $ hg --config experimental.treemanifest=True init repo
+  $ hg --config storage.treemanifest=True init repo
   $ cd repo
 
 Requirements get set on init
@@ -222,7 +222,7 @@
 Create clone with tree manifests enabled
 
   $ cd ..
-  $ hg clone --config experimental.treemanifest=1 \
+  $ hg clone --config storage.treemanifest=1 \
   >   http://localhost:$HGPORT repo-mixed -r 1
   adding changesets
   adding manifests
@@ -305,7 +305,7 @@
        0       4 064927a0648a 000000000000 000000000000
        1       5 25ecb8cb8618 000000000000 000000000000
   $ echo 2 > dir1/a
-  $ hg --config experimental.treemanifest=False ci -qm 'modify dir1/a'
+  $ hg --config storage.treemanifest=False ci -qm 'modify dir1/a'
   $ hg debugindex --dir dir1
      rev linkrev nodeid       p1           p2
        0       4 064927a0648a 000000000000 000000000000
@@ -392,7 +392,7 @@
 
 Pushing to an empty repo works
 
-  $ hg --config experimental.treemanifest=1 init clone
+  $ hg --config storage.treemanifest=1 init clone
   $ grep treemanifest clone/.hg/requires
   treemanifest
   $ hg push -R repo clone
@@ -414,7 +414,7 @@
 
 Create deeper repo with tree manifests.
 
-  $ hg --config experimental.treemanifest=True init deeprepo
+  $ hg --config storage.treemanifest=True init deeprepo
   $ cd deeprepo
 
   $ mkdir .A
@@ -673,7 +673,7 @@
   $ cat hg.pid >> $DAEMON_PIDS
   $ cd ..
 We can clone even with the knob turned off and we'll get a treemanifest repo.
-  $ hg clone --config experimental.treemanifest=False \
+  $ hg clone --config storage.treemanifest=False \
   >   --config experimental.changegroup3=True \
   >   http://localhost:$HGPORT deepclone
   requesting all changes
@@ -850,7 +850,7 @@
 
   $ mkdir grafted-dir-repo
   $ cd grafted-dir-repo
-  $ hg --config experimental.treemanifest=1 init
+  $ hg --config storage.treemanifest=1 init
   $ mkdir dir
   $ echo a > dir/file
   $ echo a > file
@@ -868,7 +868,7 @@
   created new head
   $ cd ..
 
-  $ hg --config experimental.treemanifest=1 clone --pull -r 1 \
+  $ hg --config storage.treemanifest=1 clone --pull -r 1 \
   >   grafted-dir-repo grafted-dir-repo-clone
   adding changesets
   adding manifests
diff --git a/tests/test-upgrade-repo.t b/tests/test-upgrade-repo.t
--- a/tests/test-upgrade-repo.t
+++ b/tests/test-upgrade-repo.t
@@ -35,7 +35,7 @@
 
 Do not yet support upgrading treemanifest repos
 
-  $ hg --config experimental.treemanifest=true init treemanifest
+  $ hg --config storage.treemanifest=true init treemanifest
   $ hg -R treemanifest debugupgraderepo
   abort: cannot upgrade repository; unsupported source requirement: treemanifest
   [255]
@@ -43,7 +43,7 @@
 Cannot add treemanifest requirement during upgrade
 
   $ hg init disallowaddedreq
-  $ hg -R disallowaddedreq --config experimental.treemanifest=true debugupgraderepo
+  $ hg -R disallowaddedreq --config storage.treemanifest=true debugupgraderepo
   abort: cannot upgrade repository; do not support adding requirement: treemanifest
   [255]