diff --git a/backend/src/app/rpc/commands/files_update.clj b/backend/src/app/rpc/commands/files_update.clj
index b7478a124d..06c630dfb3 100644
--- a/backend/src/app/rpc/commands/files_update.clj
+++ b/backend/src/app/rpc/commands/files_update.clj
@@ -429,6 +429,25 @@
                 :hint "branch metadata not found for branch file"
                 :file-id (:id file)))
 
+    ;; Only an open branch takes saves. A branch kept after its merge has
+    ;; its work in main, and no command integrates ops appended after the
+    ;; merge. An archived branch is read-only until it is restored or
+    ;; turned into an ordinary file. Refuse instead of stranding the ops.
+    (case (:status branch)
+      "merged"
+      (ex/raise :type :validation
+                :code :branch-merged
+                :hint "a merged branch is read-only"
+                :file-id (:id file))
+
+      "archived"
+      (ex/raise :type :validation
+                :code :branch-archived
+                :hint "an archived branch is read-only"
+                :file-id (:id file))
+
+      nil)
+
     (db/update! conn :project
                 {:modified-at modified-at}
                 {:id (:project-id file)}
diff --git a/backend/test/backend_tests/rpc_file_branch_oplog_test.clj b/backend/test/backend_tests/rpc_file_branch_oplog_test.clj
index d7996a0086..ae4b6d3a3a 100644
--- a/backend/test/backend_tests/rpc_file_branch_oplog_test.clj
+++ b/backend/test/backend_tests/rpc_file_branch_oplog_test.clj
@@ -211,6 +211,80 @@
                               (ct/is-after? deleted-at (ct/in-future {:days 400}))))
                         rows)))))))
 
+(t/deftest a-kept-merged-branch-refuses-saves
+  (with-redefs [cf/flags (conj cf/flags :branching)]
+    (let [profile (th/create-profile* 1 {:is-active true})
+          proj-id (:default-project-id profile)
+          file    (th/create-file* 1 {:profile-id (:id profile)
+                                      :project-id proj-id
+                                      :is-shared false})
+          create  (create-branch* profile (:id file) "oplog-merged")
+          branch-file-id (:branch-file-id create)
+          branch-id      (:id create)]
+
+      (th/command! {::th/type :merge-file-branch
+                    ::rpc/profile-id (:id profile)
+                    :branch-id branch-id
+                    :keep-branch true})
+
+      (let [out (apply-change* profile branch-file-id
+                               {:type :add-color
+                                :color {:id (uuid/random) :name "C" :color "#112233" :opacity 1}})]
+        (t/is (th/ex-of-type? (:error out) :validation))
+        (t/is (th/ex-of-code? (:error out) :branch-merged)))
+
+      (t/testing "nothing reaches the op log"
+        (t/is (empty? (oplog-rows branch-file-id)))))))
+
+(defn- add-color* [profile file-id]
+  (apply-change* profile file-id
+                 {:type :add-color
+                  :color {:id (uuid/random) :name "C" :color "#112233" :opacity 1}}))
+
+(defn- archived-branch*
+  "A profile and an archived branch of one of its files."
+  [name]
+  (let [profile (th/create-profile* 1 {:is-active true})
+        file    (th/create-file* 1 {:profile-id (:id profile)
+                                    :project-id (:default-project-id profile)
+                                    :is-shared false})
+        create  (create-branch* profile (:id file) name)]
+    (th/command! {::th/type :archive-file-branch
+                  ::rpc/profile-id (:id profile)
+                  :id (:id create)})
+    [profile create]))
+
+(t/deftest an-archived-branch-refuses-saves
+  (with-redefs [cf/flags (conj cf/flags :branching)]
+    (let [[profile create] (archived-branch* "oplog-archived")
+          branch-file-id   (:branch-file-id create)
+          out              (add-color* profile branch-file-id)]
+      (t/is (th/ex-of-type? (:error out) :validation))
+      (t/is (th/ex-of-code? (:error out) :branch-archived))
+      (t/is (empty? (oplog-rows branch-file-id))))))
+
+(t/deftest a-restored-branch-takes-saves-again
+  (with-redefs [cf/flags (conj cf/flags :branching)]
+    (let [[profile create] (archived-branch* "oplog-restored")
+          branch-file-id   (:branch-file-id create)]
+      (th/command! {::th/type :archive-file-branch
+                    ::rpc/profile-id (:id profile)
+                    :id (:id create)
+                    :archived false})
+      (let [out (add-color* profile branch-file-id)]
+        (t/is (nil? (:error out)))
+        (t/is (= 1 (count (oplog-rows branch-file-id))))))))
+
+(t/deftest an-archived-branch-turned-into-a-file-takes-saves
+  (with-redefs [cf/flags (conj cf/flags :branching)]
+    (let [[profile create] (archived-branch* "oplog-materialized")
+          branch-file-id   (:branch-file-id create)
+          out              (th/command! {::th/type :materialize-file-branch
+                                         ::rpc/profile-id (:id profile)
+                                         :branch-file-id branch-file-id})]
+      (t/is (nil? (:error out)))
+      (t/is (nil? (:error (add-color* profile branch-file-id)))))))
+
 (t/deftest update-from-main-compares-in-main-id-space
   ;; A branch stores no data: its document is the base snapshot plus the op
   ;; log, so every reference it inherited names MAIN. A local reference is a
diff --git a/frontend/playwright/data/pull-requests/archive-file-branch-restore.json b/frontend/playwright/data/pull-requests/archive-file-branch-restore.json
new file mode 100644
index 0000000000..0f173b4150
--- /dev/null
+++ b/frontend/playwright/data/pull-requests/archive-file-branch-restore.json
@@ -0,0 +1,4 @@
+{
+  "~:id": "~uc7ce0794-0992-8105-8004-38f280443998",
+  "~:status": "open"
+}
diff --git a/frontend/playwright/data/pull-requests/get-file-branch-info-archived.json b/frontend/playwright/data/pull-requests/get-file-branch-info-archived.json
new file mode 100644
index 0000000000..2a059deeec
--- /dev/null
+++ b/frontend/playwright/data/pull-requests/get-file-branch-info-archived.json
@@ -0,0 +1,15 @@
+{
+  "~:id": "~uc7ce0794-0992-8105-8004-38f280443998",
+  "~:branch-file-id": "~uc7ce0794-0992-8105-8004-38f280443849",
+  "~:source-file-id": "~uc7ce0794-0992-8105-8004-38f280443997",
+  "~:name": "parked",
+  "~:description": null,
+  "~:status": "archived",
+  "~:created-by": "~uc7ce0794-0992-8105-8004-38e630f29a9b",
+  "~:created-at": "~m1713536343369",
+  "~:updated-at": "~m1713873823633",
+  "~:source-name": "New File 1",
+  "~:ahead": 0,
+  "~:behind": 0,
+  "~:conflicts": 0
+}
diff --git a/frontend/playwright/data/pull-requests/get-file-branch-info-merged.json b/frontend/playwright/data/pull-requests/get-file-branch-info-merged.json
new file mode 100644
index 0000000000..0e135479ed
--- /dev/null
+++ b/frontend/playwright/data/pull-requests/get-file-branch-info-merged.json
@@ -0,0 +1,16 @@
+{
+  "~:id": "~uc7ce0794-0992-8105-8004-38f280443998",
+  "~:branch-file-id": "~uc7ce0794-0992-8105-8004-38f280443849",
+  "~:source-file-id": "~uc7ce0794-0992-8105-8004-38f280443997",
+  "~:name": "shipped",
+  "~:description": null,
+  "~:status": "merged",
+  "~:created-by": "~uc7ce0794-0992-8105-8004-38e630f29a9b",
+  "~:created-at": "~m1713536343369",
+  "~:updated-at": "~m1713873823633",
+  "~:source-name": "New File 1",
+  "~:ahead": 0,
+  "~:behind": 0,
+  "~:conflicts": 0,
+  "~:merged-at": "~m1713873823633"
+}
diff --git a/frontend/playwright/data/pull-requests/get-file-branches-closed.json b/frontend/playwright/data/pull-requests/get-file-branches-closed.json
new file mode 100644
index 0000000000..66edafc77b
--- /dev/null
+++ b/frontend/playwright/data/pull-requests/get-file-branches-closed.json
@@ -0,0 +1,32 @@
+[
+  {
+    "~:id": "~uc7ce0794-0992-8105-8004-38f280443991",
+    "~:branch-file-id": "~uc7ce0794-0992-8105-8004-38f280443851",
+    "~:source-file-id": "~uc7ce0794-0992-8105-8004-38f280443997",
+    "~:name": "shipped",
+    "~:description": null,
+    "~:status": "merged",
+    "~:created-by": "~uc7ce0794-0992-8105-8004-38e630f29a9b",
+    "~:created-at": "~m1713536343369",
+    "~:updated-at": "~m1713873823633",
+    "~:source-name": "New File 1",
+    "~:ahead": 0,
+    "~:behind": 0,
+    "~:conflicts": 0
+  },
+  {
+    "~:id": "~uc7ce0794-0992-8105-8004-38f280443992",
+    "~:branch-file-id": "~uc7ce0794-0992-8105-8004-38f280443852",
+    "~:source-file-id": "~uc7ce0794-0992-8105-8004-38f280443997",
+    "~:name": "parked",
+    "~:description": null,
+    "~:status": "archived",
+    "~:created-by": "~uc7ce0794-0992-8105-8004-38e630f29a9b",
+    "~:created-at": "~m1713536343369",
+    "~:updated-at": "~m1713873823633",
+    "~:source-name": "New File 1",
+    "~:ahead": 0,
+    "~:behind": 0,
+    "~:conflicts": 0
+  }
+]
diff --git a/frontend/playwright/ui/specs/merged-and-archived-branches.spec.js b/frontend/playwright/ui/specs/merged-and-archived-branches.spec.js
new file mode 100644
index 0000000000..3255f85e35
--- /dev/null
+++ b/frontend/playwright/ui/specs/merged-and-archived-branches.spec.js
@@ -0,0 +1,152 @@
+import { test, expect } from "@playwright/test";
+import { WorkspacePage } from "../pages/WorkspacePage";
+
+test.beforeEach(async ({ page }) => {
+  await WorkspacePage.init(page);
+  await WorkspacePage.mockConfigFlags(page, ["enable-branching"]);
+});
+
+const setupBranchFile = async (workspacePage, branchInfo) => {
+  await workspacePage.setupEmptyFile();
+  await workspacePage.mockRPCs({
+    "get-file-branch-info?file-id=*": `pull-requests/${branchInfo}`,
+    "get-file-branches?file-id=*":
+      "pull-requests/get-file-branches-closed.json",
+    "get-file-pull-requests?file-id=*":
+      "pull-requests/get-file-branches-empty.json",
+    "get-branch-diff?branch-id=*": "pull-requests/get-branch-diff-empty.json",
+  });
+};
+
+test("a kept merged branch opens read-only", async ({ page }) => {
+  const workspacePage = new WorkspacePage(page);
+  await setupBranchFile(workspacePage, "get-file-branch-info-merged.json");
+  await workspacePage.goToWorkspace();
+
+  const banner = page.locator("#branch-banner");
+  await expect(banner.getByText("Merged branch")).toBeVisible();
+  await expect(
+    banner.getByRole("button", { name: "View in main" }),
+  ).toBeVisible();
+  await expect(banner.getByRole("button", { name: "Compare" })).toBeHidden();
+  await expect(banner.getByRole("button", { name: "Restore" })).toBeHidden();
+
+  await expect(page.getByText("Merged into main, read only")).toBeVisible();
+  await expect(
+    page.getByRole("toolbar", { name: "Drawing tools" }),
+  ).toBeHidden();
+});
+
+test("an archived branch opens read-only and offers its ways out", async ({
+  page,
+}) => {
+  const workspacePage = new WorkspacePage(page);
+  await setupBranchFile(workspacePage, "get-file-branch-info-archived.json");
+  await workspacePage.mockRPC(
+    "archive-file-branch",
+    "pull-requests/archive-file-branch-restore.json",
+  );
+  await workspacePage.goToWorkspace();
+
+  const banner = page.locator("#branch-banner");
+  await expect(banner.getByText("Archived branch")).toBeVisible();
+  await expect(banner.getByText("Merged branch")).toBeHidden();
+  await expect(banner.getByRole("button", { name: "Compare" })).toBeVisible();
+  await expect(
+    banner.getByRole("button", { name: "Turn into an ordinary file" }),
+  ).toBeVisible();
+  await expect(page.getByText("Archived, read only")).toBeVisible();
+  await expect(
+    page.getByRole("toolbar", { name: "Drawing tools" }),
+  ).toBeHidden();
+
+  // restoring reopens the branch, and the banner follows its new status
+  await workspacePage.mockRPC(
+    "get-file-branch-info?file-id=*",
+    "pull-requests/get-file-branch-info-branch.json",
+  );
+  const restore = page.waitForRequest(
+    (req) =>
+      req.url().includes("archive-file-branch") &&
+      /"~:archived":\s*false/.test(req.postData() ?? ""),
+  );
+  await banner.getByRole("button", { name: "Restore" }).click();
+  await restore;
+  await expect(banner.getByText("1 change not in main")).toBeVisible();
+  await expect(
+    page.getByRole("toolbar", { name: "Drawing tools" }),
+  ).toBeVisible();
+});
+
+test("an archived branch asks before turning into an ordinary file", async ({
+  page,
+}) => {
+  const workspacePage = new WorkspacePage(page);
+  await setupBranchFile(workspacePage, "get-file-branch-info-archived.json");
+  await workspacePage.goToWorkspace();
+
+  const banner = page.locator("#branch-banner");
+  await banner
+    .getByRole("button", { name: "Turn into an ordinary file" })
+    .click();
+  await expect(
+    page.getByText("Turn this branch into an ordinary file"),
+  ).toBeVisible();
+});
+
+test("the switcher groups merged and archived branches apart", async ({
+  page,
+}) => {
+  const workspacePage = new WorkspacePage(page);
+  await setupBranchFile(workspacePage, "get-file-branch-info-none.json");
+  await workspacePage.goToWorkspace();
+
+  await page.getByTitle("Switch branch").click();
+  const popover = page.getByRole("dialog", { name: "Branches" });
+
+  await popover.getByRole("button", { name: /^Merged/ }).click();
+  await expect(popover.getByText("shipped")).toBeVisible();
+  await expect(popover.getByText("parked")).toBeHidden();
+
+  await popover.getByRole("button", { name: /^Archived/ }).click();
+  await expect(popover.getByText("parked")).toBeVisible();
+  await expect(popover.getByText("Archived, read only")).toBeVisible();
+});
+
+test("the branch list offers Restore for archived branches only", async ({
+  page,
+}) => {
+  const workspacePage = new WorkspacePage(page);
+  await setupBranchFile(workspacePage, "get-file-branch-info-none.json");
+  await workspacePage.goToWorkspace();
+
+  await page.getByTitle("Switch branch").click();
+  await page.getByText("All branches").click();
+
+  await page.getByRole("tab", { name: "Merged (1)" }).click();
+  await page.getByRole("button", { name: "Options", exact: true }).click();
+  await expect(
+    page.getByRole("menuitem", { name: "Branch info" }),
+  ).toBeVisible();
+  await expect(page.getByRole("menuitem", { name: "Restore" })).toBeHidden();
+  await expect(page.getByRole("menuitem", { name: "Compare" })).toBeHidden();
+  await expect(
+    page.getByRole("menuitem", { name: "Turn into an ordinary file" }),
+  ).toBeHidden();
+  await page.keyboard.press("Escape");
+
+  await page.getByRole("tab", { name: "Archived (1)" }).click();
+  await page.getByRole("button", { name: "Options", exact: true }).click();
+  await expect(page.getByRole("menuitem", { name: "Restore" })).toBeVisible();
+  await expect(
+    page.getByRole("menuitem", { name: "Turn into an ordinary file" }),
+  ).toBeVisible();
+  await page.getByRole("menuitem", { name: "Branch info" }).click();
+
+  const info = page.getByRole("dialog").filter({ hasText: "Branch info" });
+  await expect(info.getByRole("button", { name: "Restore" })).toBeVisible();
+  await expect(info.getByRole("button", { name: "Compare" })).toBeVisible();
+  await expect(
+    info.getByRole("button", { name: "Turn into an ordinary file" }),
+  ).toBeVisible();
+});
diff --git a/frontend/src/app/main/data/workspace/branches.cljs b/frontend/src/app/main/data/workspace/branches.cljs
index b501100e3f..be5396dc6f 100644
--- a/frontend/src/app/main/data/workspace/branches.cljs
+++ b/frontend/src/app/main/data/workspace/branches.cljs
@@ -241,6 +241,8 @@
            (rx/catch (fn [cause] (rx/of (refusal-notification cause (tr "workspace.branches.lifecycle.error")))))))))
 
 (defn archive-branch
+  "Archive a branch, or restore it with `archived?` false. The context
+  refreshes as well, so the banner of the open branch follows its status."
   ([id] (archive-branch id true))
   ([id archived?]
    (assert (uuid? id) "expected valid uuid for `id`")
@@ -248,7 +250,7 @@
      ptk/WatchEvent
      (watch [_ _ _]
        (->> (rp/cmd! :archive-file-branch {:id id :archived archived?})
-            (rx/mapcat (fn [_] (rx/of (fetch-branches))))
+            (rx/mapcat (fn [_] (rx/of (fetch-branches) (fetch-branch-context))))
             (rx/catch (fn [cause] (rx/of (refusal-notification cause (tr "workspace.branches.lifecycle.error"))))))))))
 
 (defn delete-branch
diff --git a/frontend/src/app/main/errors.cljs b/frontend/src/app/main/errors.cljs
index 274af8cf65..2f578f77df 100644
--- a/frontend/src/app/main/errors.cljs
+++ b/frontend/src/app/main/errors.cljs
@@ -526,11 +526,22 @@
 (defn flash-persistence
   [cause]
   (let [data (ex-data cause)]
-    (if (delegated-persistence-failure? data)
+    (cond
+      (delegated-persistence-failure? data)
       ;; The persistence state wraps the failure and records the original
       ;; type under :cause-type; dispatch on it to reach the cause's handler.
       (on-error (-> (exception->error-data cause)
                     (assoc :type (or (:cause-type data) (:type data)))))
+
+      ;; A merged or archived branch is read-only and the server refuses its
+      ;; saves: an expected refusal, so it is explained, not reported.
+      (= :branch-merged (:code data))
+      (st/emit! (ntf/warn (tr "errors.save-refused-merged-branch")))
+
+      (= :branch-archived (:code data))
+      (st/emit! (ntf/warn (tr "errors.save-refused-archived-branch")))
+
+      :else
       (flash :cause cause
              :type :handled
              :timeout nil
diff --git a/frontend/src/app/main/refs.cljs b/frontend/src/app/main/refs.cljs
index 4ccd578d35..377f49d116 100644
--- a/frontend/src/app/main/refs.cljs
+++ b/frontend/src/app/main/refs.cljs
@@ -74,8 +74,22 @@
                  (get projects project-id)))
              st/state))
 
+(defn- open-closed-branch?
+  "True when the open file is a merged or an archived branch. A merged
+  branch has its work in main, and an archived one is set aside until it
+  is restored or turned into an ordinary file: both open read-only."
+  [state]
+  (let [ctx (:workspace-branch-context state)]
+    (and (contains? #{"merged" "archived"} (get-in ctx [:info :status]))
+         (= (:file-id ctx) (:current-file-id state)))))
+
 (def permissions
-  (l/derived (l/key :permissions) team))
+  "The team permissions, without edition on a merged or archived branch."
+  (l/derived (fn [state]
+               (cond-> (:permissions (dsh/lookup-team state))
+                 (open-closed-branch? state)
+                 (assoc :can-edit false)))
+             st/state))
 
 (def teams
   (l/derived (l/key :teams) st/state))
diff --git a/frontend/src/app/main/ui/workspace.cljs b/frontend/src/app/main/ui/workspace.cljs
index 5355b3cf48..9c95562485 100644
--- a/frontend/src/app/main/ui/workspace.cljs
+++ b/frontend/src/app/main/ui/workspace.cljs
@@ -147,13 +147,6 @@
                 :overlay true
                 :file-loading true}])
 
-(defn- make-team-ref
-  [team-id]
-  (l/derived (fn [state]
-               (let [teams (get state :teams)]
-                 (get teams team-id)))
-             st/state))
-
 (defn- make-file-ref
   [file-id]
   (l/derived (fn [state]
@@ -213,18 +206,17 @@
   (let [layout           (mf/deref refs/workspace-layout)
         wglobal          (mf/deref refs/workspace-global)
 
-        team-ref         (mf/with-memo [team-id]
-                           (make-team-ref team-id))
         file-ref         (mf/with-memo [file-id]
                            (make-file-ref file-id))
 
-        team             (mf/deref team-ref)
         file             (mf/deref file-ref)
 
         file-loaded?     (get file ::has-data)
 
         file-name        (:name file)
-        permissions      (:permissions team)
+        ;; a merged or archived branch takes no edits: `refs/permissions`
+        ;; drops `:can-edit` for it, and the contexts below pass that on
+        permissions      (mf/deref refs/permissions)
 
         read-only?       (mf/deref refs/workspace-read-only?)
         read-only?       (or read-only? (not (:can-edit permissions)))
@@ -286,28 +278,30 @@
      [:> (mf/provider ctx/current-file-id) {:value file-id}
       [:> (mf/provider ctx/current-page-id) {:value page-id}
        [:> (mf/provider ctx/design-tokens) {:value design-tokens?}
-        [:> (mf/provider ctx/workspace-read-only?) {:value read-only?}
-         [:> modal-container*]
-         [:> components-debugger*]
-         [:section {:class (stl/css :workspace)
-                    :style {:background-color background-color
-                            :touch-action "none"
-                            :position "relative"}}
-          [:> context-menu*]
-          (when (and file-loaded? page-id)
-            [:> workspace-inner*
-             {:page-id page-id
-              :file-id file-id
-              :file file
-              :wglobal wglobal
-              :layout layout}])
-          (when (or (not (and file-loaded? page-id))
-                    ;; in wasm renderer, extend the pixel loader until the first frame is rendered
-                    ;; but do not apply it when switching pages
-                    (and wasm-renderer-enabled?
-                         (not file-loaded?)
-                         (not @first-frame-rendered?)))
-            [:> workspace-loader*])]]]]]]))
+        [:> (mf/provider ctx/permissions) {:value permissions}
+         [:> (mf/provider ctx/can-edit?) {:value (:can-edit permissions)}
+          [:> (mf/provider ctx/workspace-read-only?) {:value read-only?}
+           [:> modal-container*]
+           [:> components-debugger*]
+           [:section {:class (stl/css :workspace)
+                      :style {:background-color background-color
+                              :touch-action "none"
+                              :position "relative"}}
+            [:> context-menu*]
+            (when (and file-loaded? page-id)
+              [:> workspace-inner*
+               {:page-id page-id
+                :file-id file-id
+                :file file
+                :wglobal wglobal
+                :layout layout}])
+            (when (or (not (and file-loaded? page-id))
+                      ;; in wasm renderer, extend the pixel loader until the first frame is rendered
+                      ;; but do not apply it when switching pages
+                      (and wasm-renderer-enabled?
+                           (not file-loaded?)
+                           (not @first-frame-rendered?)))
+              [:> workspace-loader*])]]]]]]]]))
 
 (mf/defc workspace-page*
   {::mf/lazy-load true}
diff --git a/frontend/src/app/main/ui/workspace/branch_switcher.cljs b/frontend/src/app/main/ui/workspace/branch_switcher.cljs
index f03faca948..9cbf08a4cb 100644
--- a/frontend/src/app/main/ui/workspace/branch_switcher.cljs
+++ b/frontend/src/app/main/ui/workspace/branch_switcher.cljs
@@ -102,9 +102,35 @@
                     :is-current (boolean current)
                     :data-branch (dm/str (:branch-file-id row))
                     :on-click on-open}
-    (if (:is-main row)
-      (main-subtitle (:is-library row))
-      [:> row-status* {:row row :pr pr}])]])
+    ;; merged and archived branches carry no change counts
+    (cond
+      (:is-main row)              (main-subtitle (:is-library row))
+      (= "merged" (:status row))   (tr "workspace.branches.header.merged")
+      (= "archived" (:status row)) (tr "workspace.branches.header.archived")
+      :else                        [:> row-status* {:row row :pr pr}])]])
+
+(mf/defc closed-group*
+  "A collapsed section of the popover for branches out of the flow: its
+  title and count open it on click."
+  {::mf/private true}
+  [{:keys [label rows on-open]}]
+  (let [open*     (mf/use-state false)
+        open?     (deref open*)
+        on-toggle (mf/use-fn #(swap! open* not))]
+    (when (seq rows)
+      [:*
+       [:button {:class (stl/css :action)
+                 :aria-expanded open?
+                 :on-click on-toggle}
+        [:> i/icon* {:icon-id (if open? i/arrow-down i/arrow-right) :size "s"}]
+        [:span {:class (stl/css :action-label)} label]
+        [:span {:class (stl/css :action-aside)} (dm/str (count rows))]]
+       (when open?
+         [:ul {:class (stl/css :rows)}
+          (for [row rows]
+            [:> switcher-row* {:key (dm/str (:branch-file-id row))
+                               :row row
+                               :on-open on-open}])])])))
 
 (mf/defc switcher-popover*
   {::mf/private true}
@@ -113,8 +139,6 @@
 
         filter*        (mf/use-state "")
         filter-v       (deref filter*)
-        archived*      (mf/use-state false)
-        show-archived? (deref archived*)
 
         matches?
         (fn [row]
@@ -138,17 +162,13 @@
           main-row (cons main-row)
           :always  (filter matches?))
 
-        archived
-        (->> rows
-             (remove #(= "open" (:status %)))
-             (filter matches?))
+        with-status
+        (fn [status]
+          (filter #(and (= status (:status %)) (matches? %)) rows))
 
         on-filter-change
         (mf/use-fn #(reset! filter* (dom/get-target-val %)))
 
-        on-toggle-archived
-        (mf/use-fn #(swap! archived* not))
-
         on-open
         (mf/use-fn
          (fn [event]
@@ -231,20 +251,12 @@
                                  :pr (get prs-by-branch (:id row))
                                  :on-open on-open}])]])
 
-        (when (seq archived)
-          [:*
-           [:button {:class (stl/css :action)
-                     :aria-expanded show-archived?
-                     :on-click on-toggle-archived}
-            [:> i/icon* {:icon-id (if show-archived? i/arrow-down i/arrow-right) :size "s"}]
-            [:span {:class (stl/css :action-label)} (tr "workspace.branches.archived")]
-            [:span {:class (stl/css :action-aside)} (dm/str (count archived))]]
-           (when show-archived?
-             [:ul {:class (stl/css :rows)}
-              (for [row archived]
-                [:> switcher-row* {:key (dm/str (:branch-file-id row))
-                                   :row row
-                                   :on-open on-open}])])])])
+        [:> closed-group* {:label (tr "workspace.branches.merged")
+                           :rows (with-status "merged")
+                           :on-open on-open}]
+        [:> closed-group* {:label (tr "workspace.branches.archived")
+                           :rows (with-status "archived")
+                           :on-open on-open}]])
 
      [:hr {:class (stl/css :divider)}]
 
@@ -285,8 +297,6 @@
              :created-by (:id profile)
              :branch-file-id file-id})
 
-        merged?   (contains? #{"merged" "archived"} (:status ctx))
-
         ;; clicks inside the row (chip and popover) must not close it
         bar-ref   (mf/use-ref nil)
 
@@ -357,8 +367,19 @@
                       :class (stl/css :status-note)}
             (main-subtitle (:is-shared file))]
 
-           ^boolean merged?
-           nil
+           ;; merged and archived branches open read-only and count no
+           ;; changes: the note says which of the two it is
+           (= "merged" (:status ctx))
+           [:> text* {:as "span"
+                      :typography t/body-small
+                      :class (stl/css :status-note)}
+            (tr "workspace.branches.header.merged")]
+
+           (= "archived" (:status ctx))
+           [:> text* {:as "span"
+                      :typography t/body-small
+                      :class (stl/css :status-note)}
+            (tr "workspace.branches.header.archived")]
 
            (in-sync? ctx pr)
            [:> text* {:as "span"
diff --git a/frontend/src/app/main/ui/workspace/sidebar/branches.cljs b/frontend/src/app/main/ui/workspace/sidebar/branches.cljs
index 8e50fcb745..d2d3c0b908 100644
--- a/frontend/src/app/main/ui/workspace/sidebar/branches.cljs
+++ b/frontend/src/app/main/ui/workspace/sidebar/branches.cljs
@@ -439,7 +439,7 @@
                    :on-click on-submit}
        (tr "workspace.branches.merge.confirm-accept")]]]))
 
-;; --- Confirmation for relevant branch actions (merge / update)
+;; --- Confirmation for relevant branch actions (merge / update / materialize)
 
 (defn- confirm-merge!
   "Open the merge dialog for `branch` (merge into main is irreversible; the
@@ -463,6 +463,17 @@
                           :on-accept (fn [_] (st/emit! (dwb/update-branch-from-main branch
                                                                                     {:excluded excluded})))}))))
 
+(defn- confirm-materialize!
+  "Ask for confirmation before turning `branch` into an ordinary file: the
+  branch stops being one, so it can no longer be compared or merged."
+  [branch]
+  (st/emit! (modal/show {:type :confirm
+                         :title (tr "workspace.branches.materialize.title")
+                         :message (tr "workspace.branches.materialize.message" (:name branch))
+                         :accept-label (tr "workspace.branches.materialize.accept")
+                         :accept-style :danger
+                         :on-accept (fn [_] (st/emit! (dwb/materialize-branch (:branch-file-id branch))))})))
+
 ;; --- Diff counts: known, or honestly unknown
 ;;
 ;; A row whose comparison could not be made carries no counts at all (and
@@ -488,7 +499,9 @@
         author?   (= (:created-by branch) (:id profile))
         status    (:status branch)
         merged?   (= "merged" status)
-        archived? (contains? #{"archived" "merged"} status)
+        archived? (= "archived" status)
+        ;; only an open branch carries change counts
+        open?     (= "open" status)
 
         editing?  (mf/use-state false)
         desc*     (mf/use-state (or (:description branch) ""))
@@ -506,7 +519,13 @@
                                     (st/emit! (dwb/set-branch-description (:id branch) (str/trim desc)))
                                     (reset! editing? false)))
         on-compare     (mf/use-fn (mf/deps branch)
-                                  #(modal/show! :branch-compare {:branch branch}))]
+                                  #(modal/show! :branch-compare {:branch branch}))
+        on-restore     (mf/use-fn (mf/deps branch)
+                                  (fn [_]
+                                    (st/emit! (modal/hide)
+                                              (dwb/archive-branch (:id branch) false))))
+        on-materialize (mf/use-fn (mf/deps branch)
+                                  #(confirm-materialize! branch))]
     [:> modal* {:is-open true
                 :on-open-change (prui/on-dismiss on-close)}
      [:> prui/dialog-header* {:icon i/git-branch
@@ -569,7 +588,7 @@
           [:dd {:class (stl/css :info-val)}
            (some-> (:updated-at branch) ct/inst ct/timeago)]])
 
-       (when-not archived?
+       (when open?
          [:div {:class (stl/css :info-row)}
           [:dt {:class (stl/css :info-key)} (tr "workspace.branches.info.changes")]
           [:dd {:class (stl/css :info-val :info-counts)}
@@ -595,7 +614,16 @@
            (-> (:merged-at branch) ct/inst (ct/format-inst :localized-date-time))]])]]
 
      [:> modal-footer* {}
-      (when-not archived?
+      ;; an archived branch is read-only: it comes back to work restored,
+      ;; or leaves the branch engine as an ordinary file
+      (when archived?
+        [:> button* {:variant "secondary" :icon i/history :on-click on-restore}
+         (tr "workspace.branches.menu.restore")])
+      (when archived?
+        [:> button* {:variant "secondary" :icon i/document :on-click on-materialize}
+         (tr "workspace.branches.materialize.action")])
+      ;; the work of a merged branch is in main: there is nothing to compare
+      (when-not merged?
         [:> button* {:variant "secondary" :icon i/switch :on-click on-compare}
          (tr "workspace.branches.compare")])
       [:> button* {:variant "primary" :on-click on-close} (tr "labels.close")]]]))
@@ -609,7 +637,11 @@
         ahead     (:ahead entry)
         behind    (:behind entry)
         main?     (:is-main entry)
-        archived? (contains? #{"archived" "merged"} (:status entry))
+        merged?   (= "merged" (:status entry))
+        archived? (= "archived" (:status entry))
+        ;; merged and archived branches are out of the flow: no counts, no
+        ;; branch work, and dimmed in the list
+        closed?   (or merged? archived?)
 
         ;; `pr` is the branch's open pull request (nil when none): the
         ;; review is a STATE of the branch, so the entry surfaces it as a
@@ -761,15 +793,10 @@
          (fn [event]
            (dom/stop-propagation event)
            (on-set-menu false)
-           (st/emit! (modal/show {:type :confirm
-                                  :title (tr "workspace.branches.materialize.title")
-                                  :message (tr "workspace.branches.materialize.message" (:name entry))
-                                  :accept-label (tr "workspace.branches.materialize.accept")
-                                  :accept-style :danger
-                                  :on-accept (fn [_] (st/emit! (dwb/materialize-branch (:branch-file-id entry))))}))))]
+           (confirm-materialize! entry)))]
 
     [:li {:class (stl/css-case :branch-entry true
-                               :is-archived archived?
+                               :is-archived closed?
                                :is-current current)
           :role "button"
           :on-click (when-not current on-open)}
@@ -805,7 +832,7 @@
             (dm/str approvals "/" total)])])]
 
      [:div {:class (stl/css :branch-entry-aside)}
-      (when (and (not archived?) (not main?))
+      (when (and (not closed?) (not main?))
         [:div {:class (stl/css :branch-entry-counts)}
          (if (counts-error? entry)
            [:span {:class (stl/css :count-error)
@@ -839,17 +866,17 @@
                                        :on-click on-toggle-menu}])}
           [:> menu-item* {:id "info" :on-action on-info}
            (tr "workspace.branches.menu.info")]
-          (when-not archived?
+          (when-not merged?
             [:> menu-item* {:id "compare" :on-action on-compare}
              (tr "workspace.branches.compare")])
-          (when (and (not archived?) (pos? (or behind 0)))
+          (when (and (not closed?) (pos? (or behind 0)))
             [:> menu-item* {:id "update" :on-action on-update}
              (tr "workspace.branches.update")])
           ;; review lifecycle: a branch without an open pull request offers to
           ;; request one; with it, the review actions take its place (the
           ;; review either ends merging the branch or is cancelled, leaving
           ;; the branch as a normal branch again)
-          (when (and (not archived?) (dwpr/enabled?) (nil? pr))
+          (when (and (not closed?) (dwpr/enabled?) (nil? pr))
             [:> menu-item* {:id "request-review" :on-action on-request-review}
              (tr "workspace.pull-requests.menu.request-review")])
           (when (some? pr)
@@ -867,16 +894,18 @@
           (when (and (some? pr) (or author? admin?))
             [:> menu-item* {:id "cancel-review" :on-action on-cancel-review}
              (tr "workspace.pull-requests.actions.close")])
-          (when-not archived?
+          (when-not closed?
             [:> menu-item* {:id "rename" :on-action on-start-rename}
              (tr "labels.rename")])
-          [:> menu-item* {:id "archive" :on-action on-archive}
-           (tr (if archived?
-                 "workspace.branches.menu.restore"
-                 "workspace.branches.menu.archive"))]
-          ;; only an open branch can leave the branch engine: once merged or
-          ;; archived there is nothing left to turn into an ordinary file
-          (when-not archived?
+          ;; a merged branch cannot go back to work: its changes are in main
+          (when-not merged?
+            [:> menu-item* {:id "archive" :on-action on-archive}
+             (tr (if archived?
+                   "workspace.branches.menu.restore"
+                   "workspace.branches.menu.archive"))])
+          ;; a merged branch has its work in main already: only an open or an
+          ;; archived branch can leave the branch engine as an ordinary file
+          (when-not merged?
             [:> menu-item* {:id "materialize" :on-action on-materialize}
              (tr "workspace.branches.materialize.action")])
           [:> menu-item* {:id "delete" :on-action on-delete}
@@ -886,11 +915,13 @@
 
 (defn- branches-for-tab
   "The branch rows a tab of the all-branches dialog lists: the open ones,
-  the open ones the profile created, or the merged and archived ones."
+  the open ones the profile created, the merged ones, or the archived
+  ones."
   [tab rows profile-id]
   (case tab
     "mine"     (filter #(and (= "open" (:status %)) (= profile-id (:created-by %))) rows)
-    "archived" (remove #(= "open" (:status %)) rows)
+    "merged"   (filter #(= "merged" (:status %)) rows)
+    "archived" (filter #(= "archived" (:status %)) rows)
     (filter #(= "open" (:status %)) rows)))
 
 (mf/defc branches-list-dialog*
@@ -937,6 +968,7 @@
           (let [label (fn [text t] (dm/str text " (" (count (branches-for-tab t data profile-id)) ")"))]
             [{:id "mine"     :label (label (tr "workspace.branches.list.tab.mine") "mine")}
              {:id "active"   :label (label (tr "workspace.branches.list.tab.active") "active")}
+             {:id "merged"   :label (label (tr "workspace.branches.merged") "merged")}
              {:id "archived" :label (label (tr "workspace.branches.archived") "archived")}]))
 
         rows      (branches-for-tab tab matching profile-id)
@@ -1840,18 +1872,23 @@
 
 (defn- banner-status
   "What the bottom banner says about the open branch, most pressing
-  first and in the order of its primary action: merged, conflicts, main
-  moved, an open review, branch work."
+  first and in the order of its primary action: merged, archived,
+  conflicts, main moved, an open review, branch work."
   [ctx pr]
   (let [ahead     (or (:ahead ctx) 0)
         behind    (or (:behind ctx) 0)
         conflicts (or (:conflicts ctx) 0)]
     (cond
-      (contains? #{"merged" "archived"} (:status ctx))
+      (= "merged" (:status ctx))
       {:id :merged
        :icon i/git-merge
        :label (tr "workspace.branches.banner.merged")}
 
+      (= "archived" (:status ctx))
+      {:id :archived
+       :icon i/git-branch
+       :label (tr "workspace.branches.banner.archived")}
+
       (counts-error? ctx)
       {:id :counts-error
        :icon i/triangle-alert
@@ -1887,7 +1924,8 @@
 (mf/defc branch-context-banner*
   [{:keys [file-id]}]
   (let [ctx         (mf/deref branch-context)
-        merged?     (contains? #{"merged" "archived"} (:status ctx))
+        merged?     (= "merged" (:status ctx))
+        archived?   (= "archived" (:status ctx))
 
         collapsed*  (mf/use-state false)
         collapsed?  (deref collapsed*)
@@ -1915,6 +1953,8 @@
         on-compare   (mf/use-fn (mf/deps ctx) #(modal/show! :branch-compare {:branch ctx}))
         on-update    (mf/use-fn (mf/deps ctx) #(confirm-update! ctx))
         on-open-main (mf/use-fn (mf/deps ctx) #(st/emit! (dwb/open-branch (:source-file-id ctx))))
+        on-restore   (mf/use-fn (mf/deps ctx) #(st/emit! (dwb/archive-branch (:id ctx) false)))
+        on-materialize (mf/use-fn (mf/deps ctx) #(confirm-materialize! ctx))
         on-resolve   (mf/use-fn (mf/deps ctx) #(modal/show! :branch-conflicts {:branch ctx :mode :merge}))
 
         on-merge
@@ -1980,7 +2020,7 @@
       [:div {:id "branch-banner"
              :ref banner-ref
              :class (stl/css-case :branch-banner true
-                                  :branch-banner-merged merged?
+                                  :branch-banner-merged (or merged? archived?)
                                   :is-collapsed collapsed?)}
        [:button {:class (stl/css :branch-banner-handle)
                  :title (tr (if collapsed?
@@ -2001,12 +2041,32 @@
          [:span {:class (stl/css :branch-banner-title)} (:label status)]]
         [:div {:class (stl/css :branch-banner-separator)}]
 
-        (if merged?
+        (cond
+          merged?
           [:> button* {:variant "secondary"
                        :icon i/arrow-up-right
                        :on-click on-open-main}
            (tr "workspace.branches.banner.view-main")]
 
+          ;; an archived branch was set aside unmerged and is read-only: it
+          ;; can be compared with main, brought back to work, or taken out
+          ;; as an ordinary file
+          archived?
+          [:div {:class (stl/css :branch-banner-actions)}
+           [:> button* {:variant "secondary"
+                        :icon i/switch
+                        :on-click on-compare}
+            (tr "workspace.branches.compare")]
+           [:> button* {:variant "secondary"
+                        :icon i/document
+                        :on-click on-materialize}
+            (tr "workspace.branches.materialize.action")]
+           [:> button* {:variant "primary"
+                        :icon i/history
+                        :on-click on-restore}
+            (tr "workspace.branches.menu.restore")]]
+
+          :else
           (let [conflicts (or (:conflicts ctx) 0)]
             [:div {:class (stl/css :branch-banner-actions)}
              [:> button* {:variant "secondary"
diff --git a/frontend/test/frontend_tests/main_errors_test.cljs b/frontend/test/frontend_tests/main_errors_test.cljs
index a964620c15..15a73ec196 100644
--- a/frontend/test/frontend_tests/main_errors_test.cljs
+++ b/frontend/test/frontend_tests/main_errors_test.cljs
@@ -786,3 +786,22 @@
          (let [state (ptk/update (last @events) {})]
            (t/is (nil? (get-in state [:notification :timeout])))
            (t/is (some? (get-in state [:notification :links 0])))))))))
+
+(t/deftest closed-branch-save-refusals-explain-themselves
+  (t/testing "a save refused on a merged or archived branch warns without a report"
+    (doseq [code [:branch-merged :branch-archived]]
+      (let [events    (atom [])
+            scheduled (atom [])]
+        (with-redefs [st/emit!    (mock/stub (fn [& emitted] (swap! events into emitted)))
+                      tm/schedule (mock/stub (fn [callback]
+                                               (swap! scheduled conj callback)))]
+          (errors/flash-persistence (ex-info "read-only branch" {:type :validation :code code}))
+          (doseq [callback @scheduled] (callback))
+          (t/is (empty? (report-events @events)) "no error report for an expected refusal")
+          (t/is (= 1 (count @events)))
+          (let [state (ptk/update (first @events) {})]
+            (t/is (= :warning (get-in state [:notification :level])))
+            (t/is (= (i18n/tr (if (= code :branch-merged)
+                                "errors.save-refused-merged-branch"
+                                "errors.save-refused-archived-branch"))
+                     (get-in state [:notification :content])))))))))
diff --git a/frontend/translations/en.po b/frontend/translations/en.po
index a5b4bc6982..841378027e 100644
--- a/frontend/translations/en.po
+++ b/frontend/translations/en.po
@@ -1735,12 +1735,23 @@ msgstr ""
 msgid "errors.registration-disabled"
 msgstr "The registration is currently disabled."
 
-#: src/app/main/errors.cljs:538
+#: src/app/main/errors.cljs:549
 msgid "errors.save-failed"
 msgstr ""
 "Autosave is not working due to an error. Contact support to report the "
 "error and reload to continue from your last saved version."
 
+#: src/app/main/errors.cljs:542
+msgid "errors.save-refused-archived-branch"
+msgstr ""
+"This branch is archived and read only. Restore it or turn it into an "
+"ordinary file to keep editing."
+
+#: src/app/main/errors.cljs:539
+msgid "errors.save-refused-merged-branch"
+msgstr ""
+"This branch is merged into main and read only. Make your changes in main."
+
 #: src/app/main/data/persistence.cljs:307
 msgid "errors.save-retrying"
 msgstr "Connection lost. Retrying to save your changes."
@@ -6348,6 +6359,10 @@ msgstr "Ungroup"
 msgid "workspace.branches.archived"
 msgstr "Archived"
 
+#: src/app/main/ui/workspace/sidebar/branches.cljs:1840
+msgid "workspace.branches.banner.archived"
+msgstr "Archived branch"
+
 #, unused
 msgid "workspace.branches.banner.collapse"
 msgstr "Collapse"
@@ -6923,6 +6938,14 @@ msgstr "No branches yet"
 msgid "workspace.branches.header-badge-tooltip"
 msgstr "On branch %s from main"
 
+#: src/app/main/ui/workspace/branch_switcher.cljs:98, src/app/main/ui/workspace/branch_switcher.cljs:315
+msgid "workspace.branches.header.archived"
+msgstr "Archived, read only"
+
+#: src/app/main/ui/workspace/branch_switcher.cljs:97, src/app/main/ui/workspace/branch_switcher.cljs:309
+msgid "workspace.branches.header.merged"
+msgstr "Merged into main, read only"
+
 #: src/app/main/ui/workspace/branch_switcher.cljs:295
 msgid "workspace.branches.header-badge-tooltip-library"
 msgstr "On branch %s from main. Library consumers can adopt changes from main only."
@@ -7160,7 +7183,7 @@ msgstr "Default branch (read by library consumers)"
 msgid "workspace.branches.materialize.accept"
 msgstr "Turn it into a file"
 
-#: src/app/main/ui/workspace/sidebar/branches.cljs:882
+#: src/app/main/ui/workspace/sidebar/branches.cljs:609, src/app/main/ui/workspace/sidebar/branches.cljs:895, src/app/main/ui/workspace/sidebar/branches.cljs:2026
 msgid "workspace.branches.materialize.action"
 msgstr "Turn into an ordinary file"
 
@@ -7261,6 +7284,10 @@ msgstr ""
 "This branch changes elements that can't be merged automatically yet "
 "(components, pages or tokens)"
 
+#: src/app/main/ui/workspace/branch_switcher.cljs:208, src/app/main/ui/workspace/sidebar/branches.cljs:943
+msgid "workspace.branches.merged"
+msgstr "Merged"
+
 #, unused
 msgid "workspace.branches.new"
 msgstr "New"