diff --git a/web/src/hashchange.js b/web/src/hashchange.js
index d710114ce0..4a6a5b29cf 100644
--- a/web/src/hashchange.js
+++ b/web/src/hashchange.js
@@ -8,6 +8,7 @@ import * as drafts from "./drafts";
 import * as hash_util from "./hash_util";
 import {$t_html} from "./i18n";
 import * as info_overlay from "./info_overlay";
+import * as left_sidebar_navigation_area from "./left_sidebar_navigation_area";
 import * as message_lists from "./message_lists";
 import * as message_scroll from "./message_scroll";
 import * as message_viewport from "./message_viewport";
@@ -24,7 +25,6 @@ import * as settings_panel_menu from "./settings_panel_menu";
 import * as settings_toggle from "./settings_toggle";
 import * as spectators from "./spectators";
 import * as stream_settings_ui from "./stream_settings_ui";
-import * as top_left_corner from "./top_left_corner";
 import * as ui_report from "./ui_report";
 import * as user_groups_settings_ui from "./user_groups_settings_ui";
 import {user_settings} from "./user_settings";
@@ -112,7 +112,7 @@ function show_all_message_view() {
     const coming_from_recent_topics = maybe_hide_recent_topics();
     const is_actively_scrolling = message_scroll.is_actively_scrolling();
     narrow.deactivate(coming_from_recent_topics, is_actively_scrolling);
-    top_left_corner.handle_narrow_deactivated();
+    left_sidebar_navigation_area.handle_narrow_deactivated();
     // We need to maybe scroll to the selected message
     // once we have the proper viewport set up
     setTimeout(navigate.maybe_scroll_to_selected, 0);
diff --git a/web/src/top_left_corner.js b/web/src/left_sidebar_navigation_area.js
similarity index 100%
rename from web/src/top_left_corner.js
rename to web/src/left_sidebar_navigation_area.js
diff --git a/web/src/narrow.js b/web/src/narrow.js
index 91c4ce27e8..2c8c1a1a6f 100644
--- a/web/src/narrow.js
+++ b/web/src/narrow.js
@@ -15,6 +15,7 @@ import {Filter} from "./filter";
 import * as hash_util from "./hash_util";
 import * as hashchange from "./hashchange";
 import {$t} from "./i18n";
+import * as left_sidebar_navigation_area from "./left_sidebar_navigation_area";
 import * as message_edit from "./message_edit";
 import * as message_feed_loading from "./message_feed_loading";
 import * as message_feed_top_notices from "./message_feed_top_notices";
@@ -39,7 +40,6 @@ import {web_mark_read_on_scroll_policy_values} from "./settings_config";
 import * as spectators from "./spectators";
 import * as stream_data from "./stream_data";
 import * as stream_list from "./stream_list";
-import * as top_left_corner from "./top_left_corner";
 import * as topic_generator from "./topic_generator";
 import * as typing_events from "./typing_events";
 import * as unread from "./unread";
@@ -542,7 +542,7 @@ export function activate(raw_operators, opts) {
 
         const current_filter = narrow_state.filter();
 
-        top_left_corner.handle_narrow_activated(current_filter);
+        left_sidebar_navigation_area.handle_narrow_activated(current_filter);
         pm_list.handle_narrow_activated(current_filter);
         stream_list.handle_narrow_activated(current_filter);
         typing_events.render_notifications_for_narrow();
@@ -991,7 +991,7 @@ export function to_compose_target() {
 function handle_post_narrow_deactivate_processes() {
     compose_fade.update_message_list();
 
-    top_left_corner.handle_narrow_deactivated();
+    left_sidebar_navigation_area.handle_narrow_deactivated();
     pm_list.handle_narrow_deactivated();
     stream_list.handle_narrow_deactivated();
     compose_closed_ui.update_buttons_for_stream();
diff --git a/web/src/recent_topics_ui.js b/web/src/recent_topics_ui.js
index 92cacccfe3..8f821b1f88 100644
--- a/web/src/recent_topics_ui.js
+++ b/web/src/recent_topics_ui.js
@@ -11,6 +11,7 @@ import * as buddy_data from "./buddy_data";
 import * as compose_closed_ui from "./compose_closed_ui";
 import * as hash_util from "./hash_util";
 import {$t} from "./i18n";
+import * as left_sidebar_navigation_area from "./left_sidebar_navigation_area";
 import * as ListWidget from "./list_widget";
 import * as loading from "./loading";
 import {localstorage} from "./localstorage";
@@ -41,7 +42,6 @@ import * as stream_data from "./stream_data";
 import * as stream_list from "./stream_list";
 import * as sub_store from "./sub_store";
 import * as timerender from "./timerender";
-import * as top_left_corner from "./top_left_corner";
 import * as ui_util from "./ui_util";
 import * as unread from "./unread";
 import * as unread_ops from "./unread_ops";
@@ -886,7 +886,7 @@ export function show() {
         return;
     }
     // Hide selected elements in the left sidebar.
-    top_left_corner.narrow_to_recent_topics();
+    left_sidebar_navigation_area.narrow_to_recent_topics();
     stream_list.handle_narrow_deactivated();
 
     // Hide "middle-column" which has html for rendering
diff --git a/web/src/server_events_dispatch.js b/web/src/server_events_dispatch.js
index 2eb06415b5..be27a483ac 100644
--- a/web/src/server_events_dispatch.js
+++ b/web/src/server_events_dispatch.js
@@ -18,6 +18,7 @@ import * as emoji from "./emoji";
 import * as emoji_picker from "./emoji_picker";
 import * as giphy from "./giphy";
 import * as hotspots from "./hotspots";
+import * as left_sidebar_navigation_area from "./left_sidebar_navigation_area";
 import * as linkifiers from "./linkifiers";
 import * as message_edit from "./message_edit";
 import * as message_events from "./message_events";
@@ -69,7 +70,6 @@ import * as stream_topic_history from "./stream_topic_history";
 import * as stream_ui_updates from "./stream_ui_updates";
 import * as sub_store from "./sub_store";
 import * as submessage from "./submessage";
-import * as top_left_corner from "./top_left_corner";
 import * as typing_events from "./typing_events";
 import * as unread_ops from "./unread_ops";
 import * as unread_ui from "./unread_ui";
@@ -475,7 +475,7 @@ export function dispatch_normal_event(event) {
                 case "add": {
                     scheduled_messages.add_scheduled_messages(event.scheduled_messages);
                     scheduled_messages_overlay_ui.rerender();
-                    top_left_corner.update_scheduled_messages_row();
+                    left_sidebar_navigation_area.update_scheduled_messages_row();
                     break;
                 }
                 case "remove": {
@@ -483,13 +483,13 @@ export function dispatch_normal_event(event) {
                     scheduled_messages_overlay_ui.remove_scheduled_message_id(
                         event.scheduled_message_id,
                     );
-                    top_left_corner.update_scheduled_messages_row();
+                    left_sidebar_navigation_area.update_scheduled_messages_row();
                     break;
                 }
                 case "update": {
                     scheduled_messages.update_scheduled_message(event.scheduled_message);
                     scheduled_messages_overlay_ui.rerender();
-                    top_left_corner.update_scheduled_messages_row();
+                    left_sidebar_navigation_area.update_scheduled_messages_row();
                     break;
                 }
                 // No default
diff --git a/web/src/starred_messages_ui.js b/web/src/starred_messages_ui.js
index 3799540afc..d857370196 100644
--- a/web/src/starred_messages_ui.js
+++ b/web/src/starred_messages_ui.js
@@ -3,13 +3,13 @@ import render_confirm_unstar_all_messages_in_topic from "../templates/confirm_di
 
 import * as confirm_dialog from "./confirm_dialog";
 import {$t_html} from "./i18n";
+import * as left_sidebar_navigation_area from "./left_sidebar_navigation_area";
 import * as message_flags from "./message_flags";
 import * as message_live_update from "./message_live_update";
 import * as message_store from "./message_store";
 import * as popover_menus from "./popover_menus";
 import * as starred_messages from "./starred_messages";
 import * as sub_store from "./sub_store";
-import * as top_left_corner from "./top_left_corner";
 import * as unread_ops from "./unread_ops";
 import {user_settings} from "./user_settings";
 
@@ -65,7 +65,7 @@ export function rerender_ui() {
 
     popover_menus.get_topic_menu_popover()?.hide();
     popover_menus.get_starred_messages_popover()?.hide();
-    top_left_corner.update_starred_count(count);
+    left_sidebar_navigation_area.update_starred_count(count);
 }
 
 export function confirm_unstar_all_messages() {
diff --git a/web/src/ui_init.js b/web/src/ui_init.js
index 77f3262b53..e8eaa7fa2f 100644
--- a/web/src/ui_init.js
+++ b/web/src/ui_init.js
@@ -42,6 +42,7 @@ import * as hotkey from "./hotkey";
 import * as hotspots from "./hotspots";
 import * as i18n from "./i18n";
 import * as invite from "./invite";
+import * as left_sidebar_navigation_area from "./left_sidebar_navigation_area";
 import * as lightbox from "./lightbox";
 import * as linkifiers from "./linkifiers";
 import {localstorage} from "./localstorage";
@@ -104,7 +105,6 @@ import * as stream_settings_ui from "./stream_settings_ui";
 import * as sub_store from "./sub_store";
 import * as timerender from "./timerender";
 import * as tippyjs from "./tippyjs";
-import * as top_left_corner from "./top_left_corner";
 import * as topic_list from "./topic_list";
 import * as topic_zoom from "./topic_zoom";
 import * as tutorial from "./tutorial";
@@ -465,7 +465,7 @@ function initialize_unread_ui() {
         activity.update_dom_with_unread_counts(counts),
     );
     unread_ui.register_update_unread_counts_hook((counts, skip_animations) =>
-        top_left_corner.update_dom_with_unread_counts(counts, skip_animations),
+        left_sidebar_navigation_area.update_dom_with_unread_counts(counts, skip_animations),
     );
     unread_ui.register_update_unread_counts_hook((counts) =>
         stream_list.update_dom_with_unread_counts(counts),
@@ -680,7 +680,7 @@ export function initialize_everything() {
     muted_users.initialize(muted_users_params);
     stream_settings_ui.initialize();
     user_group_settings_ui.initialize();
-    top_left_corner.initialize();
+    left_sidebar_navigation_area.initialize();
     stream_list.initialize({
         on_stream_click(stream_id, trigger) {
             const sub = sub_store.get(stream_id);
diff --git a/web/tests/dispatch.test.js b/web/tests/dispatch.test.js
index fc83f00edb..ceee72de69 100644
--- a/web/tests/dispatch.test.js
+++ b/web/tests/dispatch.test.js
@@ -71,7 +71,7 @@ const stream_ui_updates = mock_esm("../src/stream_ui_updates", {
     update_announce_stream_option() {},
 });
 const submessage = mock_esm("../src/submessage");
-mock_esm("../src/top_left_corner", {
+mock_esm("../src/left_sidebar_navigation_area", {
     update_starred_count() {},
     update_scheduled_messages_row() {},
 });
diff --git a/web/tests/hashchange.test.js b/web/tests/hashchange.test.js
index ee782dc35b..c51e8763f9 100644
--- a/web/tests/hashchange.test.js
+++ b/web/tests/hashchange.test.js
@@ -26,7 +26,7 @@ const settings = mock_esm("../src/settings");
 const stream_settings_ui = mock_esm("../src/stream_settings_ui");
 const ui_util = mock_esm("../src/ui_util");
 const ui_report = mock_esm("../src/ui_report");
-mock_esm("../src/top_left_corner", {
+mock_esm("../src/left_sidebar_navigation_area", {
     handle_narrow_deactivated() {},
 });
 set_global("favicon", {});
diff --git a/web/tests/top_left_corner.test.js b/web/tests/left_sidebar_navigation_area.test.js
similarity index 76%
rename from web/tests/top_left_corner.test.js
rename to web/tests/left_sidebar_navigation_area.test.js
index 306a08a0b1..23d4162bc8 100644
--- a/web/tests/top_left_corner.test.js
+++ b/web/tests/left_sidebar_navigation_area.test.js
@@ -15,27 +15,27 @@ const scheduled_messages = mock_esm("../src/scheduled_messages");
 scheduled_messages.get_count = () => 555;
 
 const {Filter} = zrequire("../src/filter");
-const top_left_corner = zrequire("top_left_corner");
+const left_sidebar_navigation_area = zrequire("left_sidebar_navigation_area");
 
 run_test("narrowing", () => {
     let filter = new Filter([{operator: "is", operand: "mentioned"}]);
 
     // activating narrow
 
-    top_left_corner.handle_narrow_activated(filter);
+    left_sidebar_navigation_area.handle_narrow_activated(filter);
     assert.ok($(".top_left_mentions").hasClass("active-filter"));
 
     filter = new Filter([{operator: "is", operand: "starred"}]);
-    top_left_corner.handle_narrow_activated(filter);
+    left_sidebar_navigation_area.handle_narrow_activated(filter);
     assert.ok($(".top_left_starred_messages").hasClass("active-filter"));
 
     filter = new Filter([{operator: "in", operand: "home"}]);
-    top_left_corner.handle_narrow_activated(filter);
+    left_sidebar_navigation_area.handle_narrow_activated(filter);
     assert.ok($(".top_left_all_messages").hasClass("active-filter"));
 
     // deactivating narrow
 
-    top_left_corner.handle_narrow_deactivated();
+    left_sidebar_navigation_area.handle_narrow_deactivated();
 
     assert.ok($(".top_left_all_messages").hasClass("active-filter"));
     assert.ok(!$(".top_left_mentions").hasClass("active-filter"));
@@ -45,7 +45,7 @@ run_test("narrowing", () => {
     set_global("setTimeout", (f) => {
         f();
     });
-    top_left_corner.narrow_to_recent_topics();
+    left_sidebar_navigation_area.narrow_to_recent_topics();
     assert.ok(!$(".top_left_all_messages").hasClass("active-filter"));
     assert.ok(!$(".top_left_mentions").hasClass("active-filter"));
     assert.ok(!$(".top_left_starred_messages").hasClass("active-filter"));
@@ -74,10 +74,10 @@ run_test("update_count_in_dom", () => {
 
     make_elem($(".top_left_scheduled_messages"), "<scheduled-count>");
 
-    top_left_corner.update_dom_with_unread_counts(counts, false);
-    top_left_corner.update_starred_count(444);
-    // Calls top_left_corner.update_scheduled_messages_row
-    top_left_corner.initialize();
+    left_sidebar_navigation_area.update_dom_with_unread_counts(counts, false);
+    left_sidebar_navigation_area.update_starred_count(444);
+    // Calls left_sidebar_navigation_area.update_scheduled_messages_row
+    left_sidebar_navigation_area.initialize();
 
     assert.equal($("<mentioned-count>").text(), "222");
     assert.equal($("<home-count>").text(), "333");
@@ -87,9 +87,9 @@ run_test("update_count_in_dom", () => {
     counts.mentioned_message_count = 0;
     scheduled_messages.get_count = () => 0;
 
-    top_left_corner.update_dom_with_unread_counts(counts, false);
-    top_left_corner.update_starred_count(0);
-    top_left_corner.update_scheduled_messages_row();
+    left_sidebar_navigation_area.update_dom_with_unread_counts(counts, false);
+    left_sidebar_navigation_area.update_starred_count(0);
+    left_sidebar_navigation_area.update_scheduled_messages_row();
 
     assert.ok(!$("<mentioned-count>").visible());
     assert.equal($("<mentioned-count>").text(), "");
diff --git a/web/tests/message_flags.test.js b/web/tests/message_flags.test.js
index 66556e704d..b512069174 100644
--- a/web/tests/message_flags.test.js
+++ b/web/tests/message_flags.test.js
@@ -16,7 +16,7 @@ mock_esm("../src/starred_messages", {
     get_starred_msg_ids: () => [1, 2, 3, 4, 5],
     remove() {},
 });
-mock_esm("../src/top_left_corner", {
+mock_esm("../src/left_sidebar_navigation_area", {
     update_starred_count() {},
 });
 
diff --git a/web/tests/narrow_activate.test.js b/web/tests/narrow_activate.test.js
index d3e3fe1384..d36f41402f 100644
--- a/web/tests/narrow_activate.test.js
+++ b/web/tests/narrow_activate.test.js
@@ -29,7 +29,7 @@ const message_feed_loading = mock_esm("../src/message_feed_loading");
 const message_view_header = mock_esm("../src/message_view_header");
 const notifications = mock_esm("../src/notifications");
 const stream_list = mock_esm("../src/stream_list");
-const top_left_corner = mock_esm("../src/top_left_corner");
+const left_sidebar_navigation_area = mock_esm("../src/left_sidebar_navigation_area");
 const typing_events = mock_esm("../src/typing_events");
 const unread_ops = mock_esm("../src/unread_ops");
 mock_esm("../src/recent_topics_util", {
@@ -89,7 +89,7 @@ function test_helper() {
     stub(notifications, "redraw_title");
     stub(stream_list, "handle_narrow_activated");
     stub(message_view_header, "render_title_area");
-    stub(top_left_corner, "handle_narrow_activated");
+    stub(left_sidebar_navigation_area, "handle_narrow_activated");
     stub(typing_events, "render_notifications_for_narrow");
     stub(compose_recipient, "update_narrow_to_recipient_visibility");
     stub(unread_ops, "process_visible");
@@ -192,7 +192,7 @@ run_test("basics", () => {
         [compose_closed_ui, "update_buttons_for_stream"],
         [compose_closed_ui, "update_reply_recipient_label"],
         [compose_actions, "on_narrow"],
-        [top_left_corner, "handle_narrow_activated"],
+        [left_sidebar_navigation_area, "handle_narrow_activated"],
         [stream_list, "handle_narrow_activated"],
         [typing_events, "render_notifications_for_narrow"],
         [message_view_header, "render_title_area"],
diff --git a/web/tests/recent_topics.test.js b/web/tests/recent_topics.test.js
index 250721d02f..649b228244 100644
--- a/web/tests/recent_topics.test.js
+++ b/web/tests/recent_topics.test.js
@@ -155,7 +155,7 @@ mock_esm("../src/sub_store", {
         };
     },
 });
-mock_esm("../src/top_left_corner", {
+mock_esm("../src/left_sidebar_navigation_area", {
     narrow_to_recent_topics: noop,
 });
 mock_esm("../src/unread", {
diff --git a/web/tests/starred_messages.test.js b/web/tests/starred_messages.test.js
index b8c65570c1..0dffb0e004 100644
--- a/web/tests/starred_messages.test.js
+++ b/web/tests/starred_messages.test.js
@@ -7,7 +7,7 @@ const {make_stub} = require("./lib/stub");
 const {run_test} = require("./lib/test");
 const {user_settings} = require("./lib/zpage_params");
 
-const top_left_corner = mock_esm("../src/top_left_corner", {
+const left_sidebar_navigation_area = mock_esm("../src/left_sidebar_navigation_area", {
     update_starred_count() {},
 });
 const message_store = zrequire("message_store");
@@ -99,7 +99,7 @@ run_test("rerender_ui", () => {
     user_settings.starred_message_counts = true;
     with_overrides(({override}) => {
         const stub = make_stub();
-        override(top_left_corner, "update_starred_count", stub.f);
+        override(left_sidebar_navigation_area, "update_starred_count", stub.f);
         starred_messages_ui.rerender_ui();
         assert.equal(stub.num_calls, 1);
         const args = stub.get_args("count");
@@ -109,7 +109,7 @@ run_test("rerender_ui", () => {
     user_settings.starred_message_counts = false;
     with_overrides(({override}) => {
         const stub = make_stub();
-        override(top_left_corner, "update_starred_count", stub.f);
+        override(left_sidebar_navigation_area, "update_starred_count", stub.f);
         starred_messages_ui.rerender_ui();
         assert.equal(stub.num_calls, 1);
         const args = stub.get_args("count");