diff --git a/.eslintrc-test-paths.js b/.eslintrc-test-paths.js
index 2e4a1ec939770433749029b168cc16bb04ecb5de..3beca52b054d59bd95e1d11fee70b756eb77086f 100644
--- a/.eslintrc-test-paths.js
+++ b/.eslintrc-test-paths.js
@@ -130,8 +130,6 @@ const extraBrowserTestPaths = [
   "browser/components/safebrowsing/content/test/",
   "browser/components/sessionstore/test/",
   "browser/components/shell/test/",
-  "browser/components/tabbrowser/test/statuspanel/",
-  "browser/components/tabbrowser/test/tabs/",
   "browser/components/touchbar/tests/",
   "browser/components/uitour/test/",
   "browser/extensions/report-site-issue/test/browser/",
diff --git a/.prettierignore b/.prettierignore
index c3b6362686d644fa63ede0a28badfb63fb5c26c2..64998e44c37cb0b2391dc1f6054526b633fd7b12 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -191,9 +191,9 @@ browser/components/sessionstore/test/browser_423132_sample.html
 browser/components/sessionstore/test/browser_485482_sample.html
 browser/components/sessionstore/test/browser_frametree_sample_frameset.html
 browser/components/sessionstore/test/browser_scrollPositions_sample_frameset.html
-browser/components/tabbrowser/test/tabs/dummy_page.html
-browser/components/tabbrowser/test/tabs/file_anchor_elements.html
-browser/components/tabbrowser/test/tabs/tab_that_closes.html
+browser/components/tabbrowser/test/browser/tabs/dummy_page.html
+browser/components/tabbrowser/test/browser/tabs/file_anchor_elements.html
+browser/components/tabbrowser/test/browser/tabs/tab_that_closes.html
 browser/components/textrecognition/textrecognition.html
 browser/components/urlbar/content/quicksuggestOnboarding.html
 browser/components/urlbar/tests/browser/dummy_page.html
diff --git a/browser/components/contextualidentity/test/browser/browser_originattrs_reopenin.js b/browser/components/contextualidentity/test/browser/browser_originattrs_reopenin.js
index 9ee27f638d337afc737a5b6a2cb02df3230fa385..a016bd77d616caef56622bd4b74e84aba8615edd 100644
--- a/browser/components/contextualidentity/test/browser/browser_originattrs_reopenin.js
+++ b/browser/components/contextualidentity/test/browser/browser_originattrs_reopenin.js
@@ -2,9 +2,9 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/* import-globals-from ../../../tabbrowser/test/tabs/helper_origin_attrs_testing.js */
+/* import-globals-from ../../../tabbrowser/test/browser/tabs/helper_origin_attrs_testing.js */
 loadTestSubscript(
-  "../../../tabbrowser/test/tabs/helper_origin_attrs_testing.js"
+  "../../../tabbrowser/test/browser/tabs/helper_origin_attrs_testing.js"
 );
 
 const PATH =
diff --git a/browser/components/sessionstore/test/browser_restore_container_tabs_oa.js b/browser/components/sessionstore/test/browser_restore_container_tabs_oa.js
index b981c20c3095a5337c3ca1a98dc652609d017c8d..e01cb4c727e2ce7b705057095a9715c06ad60023 100644
--- a/browser/components/sessionstore/test/browser_restore_container_tabs_oa.js
+++ b/browser/components/sessionstore/test/browser_restore_container_tabs_oa.js
@@ -10,8 +10,10 @@ const { UrlbarProviderOpenTabs } = ChromeUtils.importESModule(
 
 const PATH = "browser/browser/components/sessionstore/test/empty.html";
 
-/* import-globals-from ../../tabbrowser/test/tabs/helper_origin_attrs_testing.js */
-loadTestSubscript("../../tabbrowser/test/tabs/helper_origin_attrs_testing.js");
+/* import-globals-from ../../tabbrowser/test/browser/tabs/helper_origin_attrs_testing.js */
+loadTestSubscript(
+  "../../tabbrowser/test/browser/tabs/helper_origin_attrs_testing.js"
+);
 
 var TEST_CASES = [
   "https://example.com/" + PATH,
diff --git a/browser/components/sessionstore/test/browser_restored_window_features.js b/browser/components/sessionstore/test/browser_restored_window_features.js
index 0398df0c13a4231aa57295b415c14724dca9e1fb..e3745df2a36eb93b10d1d6560a3f11965e1f9aea 100644
--- a/browser/components/sessionstore/test/browser_restored_window_features.js
+++ b/browser/components/sessionstore/test/browser_restored_window_features.js
@@ -38,7 +38,8 @@ function testFeatures(win, test) {
 }
 
 add_task(async function testRestoredWindowFeatures() {
-  const DUMMY_PAGE = "browser/components/tabbrowser/test/tabs/dummy_page.html";
+  const DUMMY_PAGE =
+    "browser/components/tabbrowser/test/browser/tabs/dummy_page.html";
   const ALL_BARPROPS = {
     locationbar: true,
     menubar: true,
diff --git a/browser/components/tabbrowser/moz.build b/browser/components/tabbrowser/moz.build
index 3be9cfe1b2db6876617ebdd5ff74ea4eae7070a0..75145a0e3db4d8d5de16b85611490bcb1ae72ad2 100644
--- a/browser/components/tabbrowser/moz.build
+++ b/browser/components/tabbrowser/moz.build
@@ -16,6 +16,6 @@ EXTRA_JS_MODULES += [
 ]
 
 BROWSER_CHROME_MANIFESTS += [
-    "test/statuspanel/browser.toml",
-    "test/tabs/browser.toml",
+    "test/browser/statuspanel/browser.toml",
+    "test/browser/tabs/browser.toml",
 ]
diff --git a/browser/components/tabbrowser/test/statuspanel/browser.toml b/browser/components/tabbrowser/test/browser/statuspanel/browser.toml
similarity index 100%
rename from browser/components/tabbrowser/test/statuspanel/browser.toml
rename to browser/components/tabbrowser/test/browser/statuspanel/browser.toml
diff --git a/browser/components/tabbrowser/test/statuspanel/browser_show_statuspanel_idn.js b/browser/components/tabbrowser/test/browser/statuspanel/browser_show_statuspanel_idn.js
similarity index 100%
rename from browser/components/tabbrowser/test/statuspanel/browser_show_statuspanel_idn.js
rename to browser/components/tabbrowser/test/browser/statuspanel/browser_show_statuspanel_idn.js
diff --git a/browser/components/tabbrowser/test/statuspanel/browser_show_statuspanel_twice.js b/browser/components/tabbrowser/test/browser/statuspanel/browser_show_statuspanel_twice.js
similarity index 100%
rename from browser/components/tabbrowser/test/statuspanel/browser_show_statuspanel_twice.js
rename to browser/components/tabbrowser/test/browser/statuspanel/browser_show_statuspanel_twice.js
diff --git a/browser/components/tabbrowser/test/statuspanel/head.js b/browser/components/tabbrowser/test/browser/statuspanel/head.js
similarity index 100%
rename from browser/components/tabbrowser/test/statuspanel/head.js
rename to browser/components/tabbrowser/test/browser/statuspanel/head.js
diff --git a/browser/components/tabbrowser/test/tabs/204.sjs b/browser/components/tabbrowser/test/browser/tabs/204.sjs
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/204.sjs
rename to browser/components/tabbrowser/test/browser/tabs/204.sjs
diff --git a/browser/components/tabbrowser/test/tabs/audio.ogg b/browser/components/tabbrowser/test/browser/tabs/audio.ogg
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/audio.ogg
rename to browser/components/tabbrowser/test/browser/tabs/audio.ogg
diff --git a/browser/components/tabbrowser/test/tabs/blank.html b/browser/components/tabbrowser/test/browser/tabs/blank.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/blank.html
rename to browser/components/tabbrowser/test/browser/tabs/blank.html
diff --git a/browser/components/tabbrowser/test/tabs/browser.toml b/browser/components/tabbrowser/test/browser/tabs/browser.toml
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser.toml
rename to browser/components/tabbrowser/test/browser/tabs/browser.toml
diff --git a/browser/components/tabbrowser/test/tabs/browser_addAdjacentNewTab.js b/browser/components/tabbrowser/test/browser/tabs/browser_addAdjacentNewTab.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_addAdjacentNewTab.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_addAdjacentNewTab.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_addTab_index.js b/browser/components/tabbrowser/test/browser/tabs/browser_addTab_index.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_addTab_index.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_addTab_index.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_adoptTab_failure.js b/browser/components/tabbrowser/test/browser/tabs/browser_adoptTab_failure.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_adoptTab_failure.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_adoptTab_failure.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_allow_process_switches_despite_related_browser.js b/browser/components/tabbrowser/test/browser/tabs/browser_allow_process_switches_despite_related_browser.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_allow_process_switches_despite_related_browser.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_allow_process_switches_despite_related_browser.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_audioTabIcon.js b/browser/components/tabbrowser/test/browser/tabs/browser_audioTabIcon.js
similarity index 99%
rename from browser/components/tabbrowser/test/tabs/browser_audioTabIcon.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_audioTabIcon.js
index a79605f8f3392e615277e1345070323b0271e5b3..189258b4faa83099d06998232f381b6f0a718399 100644
--- a/browser/components/tabbrowser/test/tabs/browser_audioTabIcon.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_audioTabIcon.js
@@ -1,6 +1,6 @@
 /* eslint-disable mozilla/no-arbitrary-setTimeout */
 const PAGE =
-  "https://example.com/browser/browser/components/tabbrowser/test/tabs/file_mediaPlayback.html";
+  "https://example.com/browser/browser/components/tabbrowser/test/browser/tabs/file_mediaPlayback.html";
 const TABATTR_REMOVAL_PREFNAME = "browser.tabs.delayHidingAudioPlayingIconMS";
 const INITIAL_TABATTR_REMOVAL_DELAY_MS = Services.prefs.getIntPref(
   TABATTR_REMOVAL_PREFNAME
diff --git a/browser/components/tabbrowser/test/tabs/browser_bfcache_exemption_about_pages.js b/browser/components/tabbrowser/test/browser/tabs/browser_bfcache_exemption_about_pages.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_bfcache_exemption_about_pages.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_bfcache_exemption_about_pages.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_blank_tab_label.js b/browser/components/tabbrowser/test/browser/tabs/browser_blank_tab_label.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_blank_tab_label.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_blank_tab_label.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_bug580956.js b/browser/components/tabbrowser/test/browser/tabs/browser_bug580956.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_bug580956.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_bug580956.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_bug_1387976_restore_lazy_tab_browser_muted_state.js b/browser/components/tabbrowser/test/browser/tabs/browser_bug_1387976_restore_lazy_tab_browser_muted_state.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_bug_1387976_restore_lazy_tab_browser_muted_state.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_bug_1387976_restore_lazy_tab_browser_muted_state.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_close_during_beforeunload.js b/browser/components/tabbrowser/test/browser/tabs/browser_close_during_beforeunload.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_close_during_beforeunload.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_close_during_beforeunload.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_close_tab_by_dblclick.js b/browser/components/tabbrowser/test/browser/tabs/browser_close_tab_by_dblclick.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_close_tab_by_dblclick.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_close_tab_by_dblclick.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_contextmenu_openlink_after_tabnavigated.js b/browser/components/tabbrowser/test/browser/tabs/browser_contextmenu_openlink_after_tabnavigated.js
similarity index 99%
rename from browser/components/tabbrowser/test/tabs/browser_contextmenu_openlink_after_tabnavigated.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_contextmenu_openlink_after_tabnavigated.js
index 3c207833c67dd1e51525bed20217217247a8e7bb..5acc83c465938f75edd1a7330c01a40a09f4f7ce 100644
--- a/browser/components/tabbrowser/test/tabs/browser_contextmenu_openlink_after_tabnavigated.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_contextmenu_openlink_after_tabnavigated.js
@@ -2,7 +2,7 @@
 
 const example_base =
   // eslint-disable-next-line @microsoft/sdl/no-insecure-url
-  "http://example.com/browser/browser/components/tabbrowser/test/tabs/";
+  "http://example.com/browser/browser/components/tabbrowser/test/browser/tabs/";
 
 add_task(async function test_contextmenu_openlink_after_tabnavigated() {
   let url = example_base + "test_bug1358314.html";
diff --git a/browser/components/tabbrowser/test/tabs/browser_dont_process_switch_204.js b/browser/components/tabbrowser/test/browser/tabs/browser_dont_process_switch_204.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_dont_process_switch_204.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_dont_process_switch_204.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_e10s_about_page_triggeringprincipal.js b/browser/components/tabbrowser/test/browser/tabs/browser_e10s_about_page_triggeringprincipal.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_e10s_about_page_triggeringprincipal.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_e10s_about_page_triggeringprincipal.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_e10s_about_process.js b/browser/components/tabbrowser/test/browser/tabs/browser_e10s_about_process.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_e10s_about_process.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_e10s_about_process.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_e10s_chrome_process.js b/browser/components/tabbrowser/test/browser/tabs/browser_e10s_chrome_process.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_e10s_chrome_process.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_e10s_chrome_process.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_e10s_javascript.js b/browser/components/tabbrowser/test/browser/tabs/browser_e10s_javascript.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_e10s_javascript.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_e10s_javascript.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_e10s_mozillaweb_process.js b/browser/components/tabbrowser/test/browser/tabs/browser_e10s_mozillaweb_process.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_e10s_mozillaweb_process.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_e10s_mozillaweb_process.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_e10s_switchbrowser.js b/browser/components/tabbrowser/test/browser/tabs/browser_e10s_switchbrowser.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_e10s_switchbrowser.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_e10s_switchbrowser.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_file_to_http_named_popup.js b/browser/components/tabbrowser/test/browser/tabs/browser_file_to_http_named_popup.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_file_to_http_named_popup.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_file_to_http_named_popup.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_file_to_http_script_closable.js b/browser/components/tabbrowser/test/browser/tabs/browser_file_to_http_script_closable.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_file_to_http_script_closable.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_file_to_http_script_closable.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_hiddentab_contextmenu.js b/browser/components/tabbrowser/test/browser/tabs/browser_hiddentab_contextmenu.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_hiddentab_contextmenu.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_hiddentab_contextmenu.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_lastSeenActive.js b/browser/components/tabbrowser/test/browser/tabs/browser_lastSeenActive.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_lastSeenActive.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_lastSeenActive.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_lazy_tab_browser_events.js b/browser/components/tabbrowser/test/browser/tabs/browser_lazy_tab_browser_events.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_lazy_tab_browser_events.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_lazy_tab_browser_events.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_blank_page.js b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_blank_page.js
similarity index 98%
rename from browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_blank_page.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_blank_page.js
index feb52c044a2b00b04c25230c6aad71711083339f..5d59a110b99049d24ccd7b214a8a99216bc58de8 100644
--- a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_blank_page.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_blank_page.js
@@ -10,7 +10,7 @@ ChromeUtils.defineESModuleGetters(this, {
 
 /* import-globals-from common_link_in_tab_title_and_url_prefilled.js */
 Services.scriptloader.loadSubScript(
-  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/tabs/common_link_in_tab_title_and_url_prefilled.js",
+  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/browser/tabs/common_link_in_tab_title_and_url_prefilled.js",
   this
 );
 
diff --git a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_new_window.js b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_new_window.js
similarity index 95%
rename from browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_new_window.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_new_window.js
index 0dbf4647c250fd9bea31b860126599f91464573b..dc1cbd2c1c457e6a1c199c0bf00896101bae2764 100644
--- a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_new_window.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_new_window.js
@@ -7,7 +7,7 @@
 
 /* import-globals-from common_link_in_tab_title_and_url_prefilled.js */
 Services.scriptloader.loadSubScript(
-  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/tabs/common_link_in_tab_title_and_url_prefilled.js",
+  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/browser/tabs/common_link_in_tab_title_and_url_prefilled.js",
   this
 );
 
diff --git a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_blank_target.js b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_blank_target.js
similarity index 98%
rename from browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_blank_target.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_blank_target.js
index 705811564c1d4578e62a3ea883bd8e5ad00724fb..84f18db36565bb4850f75bb57b157f15e3a17660 100644
--- a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_blank_target.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_blank_target.js
@@ -11,7 +11,7 @@ ChromeUtils.defineESModuleGetters(this, {
 
 /* import-globals-from common_link_in_tab_title_and_url_prefilled.js */
 Services.scriptloader.loadSubScript(
-  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/tabs/common_link_in_tab_title_and_url_prefilled.js",
+  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/browser/tabs/common_link_in_tab_title_and_url_prefilled.js",
   this
 );
 
diff --git a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_by_script.js b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_by_script.js
similarity index 97%
rename from browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_by_script.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_by_script.js
index 0773541296a4df224a76736fa92ae2c72b8649e5..37d3379e91076f4ba078326cd70f60f433c3d21a 100644
--- a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_by_script.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_by_script.js
@@ -7,7 +7,7 @@
 
 /* import-globals-from common_link_in_tab_title_and_url_prefilled.js */
 Services.scriptloader.loadSubScript(
-  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/tabs/common_link_in_tab_title_and_url_prefilled.js",
+  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/browser/tabs/common_link_in_tab_title_and_url_prefilled.js",
   this
 );
 const { UrlbarTestUtils } = ChromeUtils.importESModule(
diff --git a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_no_target.js b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_no_target.js
similarity index 97%
rename from browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_no_target.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_no_target.js
index 15aff9f8e1f68b87b09180fda06743c6993d8900..469e33478e8903702e42a97fe2a93ac904818e01 100644
--- a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_no_target.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_no_target.js
@@ -7,7 +7,7 @@
 
 /* import-globals-from common_link_in_tab_title_and_url_prefilled.js */
 Services.scriptloader.loadSubScript(
-  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/tabs/common_link_in_tab_title_and_url_prefilled.js",
+  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/browser/tabs/common_link_in_tab_title_and_url_prefilled.js",
   this
 );
 
diff --git a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_other_target.js b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_other_target.js
similarity index 98%
rename from browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_other_target.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_other_target.js
index f97e4dec9815278a9799b49abcc221e3628ef1e0..bd6e3a31b52c1dd6282c9aa96d2e5d2ae407a6da 100644
--- a/browser/components/tabbrowser/test/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_other_target.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_link_in_tab_title_and_url_prefilled_normal_page_other_target.js
@@ -11,7 +11,7 @@ ChromeUtils.defineESModuleGetters(this, {
 
 /* import-globals-from common_link_in_tab_title_and_url_prefilled.js */
 Services.scriptloader.loadSubScript(
-  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/tabs/common_link_in_tab_title_and_url_prefilled.js",
+  "chrome://mochitests/content/browser/browser/components/tabbrowser/test/browser/tabs/common_link_in_tab_title_and_url_prefilled.js",
   this
 );
 
diff --git a/browser/components/tabbrowser/test/tabs/browser_long_data_url_label_truncation.js b/browser/components/tabbrowser/test/browser/tabs/browser_long_data_url_label_truncation.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_long_data_url_label_truncation.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_long_data_url_label_truncation.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_middle_click_new_tab_button_loads_clipboard.js b/browser/components/tabbrowser/test/browser/tabs/browser_middle_click_new_tab_button_loads_clipboard.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_middle_click_new_tab_button_loads_clipboard.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_middle_click_new_tab_button_loads_clipboard.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_active_tab_selected_by_default.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_active_tab_selected_by_default.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_active_tab_selected_by_default.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_active_tab_selected_by_default.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_bookmark.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_bookmark.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_bookmark.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_bookmark.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_clear_selection_when_tab_switch.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_clear_selection_when_tab_switch.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_clear_selection_when_tab_switch.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_clear_selection_when_tab_switch.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_duplicate_tabs.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_duplicate_tabs.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_duplicate_tabs.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_duplicate_tabs.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_other_tabs.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_other_tabs.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_other_tabs.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_other_tabs.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_tabs_to_the_left.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_tabs_to_the_left.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_tabs_to_the_left.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_tabs_to_the_left.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_tabs_to_the_right.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_tabs_to_the_right.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_tabs_to_the_right.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_tabs_to_the_right.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_using_shortcuts.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_using_shortcuts.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_close_using_shortcuts.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_close_using_shortcuts.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_copy_through_drag_and_drop.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_copy_through_drag_and_drop.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_copy_through_drag_and_drop.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_copy_through_drag_and_drop.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_drag_to_bookmarks_toolbar.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_drag_to_bookmarks_toolbar.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_drag_to_bookmarks_toolbar.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_drag_to_bookmarks_toolbar.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_duplicate.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_duplicate.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_duplicate.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_duplicate.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_event.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_event.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_event.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_event.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_move.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_move.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_move.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_move.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_move_to_another_window_drag.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_move_to_another_window_drag.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_move_to_another_window_drag.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_move_to_another_window_drag.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_move_to_new_window_contextmenu.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_move_to_new_window_contextmenu.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_move_to_new_window_contextmenu.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_move_to_new_window_contextmenu.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_mute_unmute.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_mute_unmute.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_mute_unmute.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_mute_unmute.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_open_related.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_open_related.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_open_related.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_open_related.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_pin_unpin.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_pin_unpin.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_pin_unpin.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_pin_unpin.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_play.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_play.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_play.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_play.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_reload.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_reload.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_reload.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_reload.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_reopen_in_container.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_reopen_in_container.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_reopen_in_container.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_reopen_in_container.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_reorder.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_reorder.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_reorder.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_reorder.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_Ctrl.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_Ctrl.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_Ctrl.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_Ctrl.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_Shift.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_Shift.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_Shift.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_Shift.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_Shift_and_Ctrl.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_Shift_and_Ctrl.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_Shift_and_Ctrl.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_Shift_and_Ctrl.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_keyboard.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_keyboard.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_keyboard.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_keyboard.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_selectedTabs.js b/browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_selectedTabs.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_multiselect_tabs_using_selectedTabs.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_multiselect_tabs_using_selectedTabs.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_navigatePinnedTab.js b/browser/components/tabbrowser/test/browser/tabs/browser_navigatePinnedTab.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_navigatePinnedTab.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_navigatePinnedTab.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_navigate_home_focuses_addressbar.js b/browser/components/tabbrowser/test/browser/tabs/browser_navigate_home_focuses_addressbar.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_navigate_home_focuses_addressbar.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_navigate_home_focuses_addressbar.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_navigate_through_urls_origin_attributes.js b/browser/components/tabbrowser/test/browser/tabs/browser_navigate_through_urls_origin_attributes.js
similarity index 98%
rename from browser/components/tabbrowser/test/tabs/browser_navigate_through_urls_origin_attributes.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_navigate_through_urls_origin_attributes.js
index 7a993631377604dba03a77daee12bf30423d048c..e47ecbd65c79c56001162d24f274a1c7c0b1a184 100644
--- a/browser/components/tabbrowser/test/tabs/browser_navigate_through_urls_origin_attributes.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_navigate_through_urls_origin_attributes.js
@@ -5,7 +5,8 @@
 /* import-globals-from helper_origin_attrs_testing.js */
 loadTestSubscript("helper_origin_attrs_testing.js");
 
-const PATH = "browser/browser/components/tabbrowser/test/tabs/blank.html";
+const PATH =
+  "browser/browser/components/tabbrowser/test/browser/tabs/blank.html";
 
 var TEST_CASES = [
   { uri: "https://example.com/" + PATH },
diff --git a/browser/components/tabbrowser/test/tabs/browser_new_file_whitelisted_http_tab.js b/browser/components/tabbrowser/test/browser/tabs/browser_new_file_whitelisted_http_tab.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_new_file_whitelisted_http_tab.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_new_file_whitelisted_http_tab.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_new_tab_bookmarks_toolbar_height.js b/browser/components/tabbrowser/test/browser/tabs/browser_new_tab_bookmarks_toolbar_height.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_new_tab_bookmarks_toolbar_height.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_new_tab_bookmarks_toolbar_height.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_new_tab_in_privilegedabout_process_pref.js b/browser/components/tabbrowser/test/browser/tabs/browser_new_tab_in_privilegedabout_process_pref.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_new_tab_in_privilegedabout_process_pref.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_new_tab_in_privilegedabout_process_pref.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_new_tab_insert_position.js b/browser/components/tabbrowser/test/browser/tabs/browser_new_tab_insert_position.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_new_tab_insert_position.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_new_tab_insert_position.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_new_tab_url.js b/browser/components/tabbrowser/test/browser/tabs/browser_new_tab_url.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_new_tab_url.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_new_tab_url.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_newwindow_tabstrip_overflow.js b/browser/components/tabbrowser/test/browser/tabs/browser_newwindow_tabstrip_overflow.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_newwindow_tabstrip_overflow.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_newwindow_tabstrip_overflow.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_openURI_background.js b/browser/components/tabbrowser/test/browser/tabs/browser_openURI_background.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_openURI_background.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_openURI_background.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_open_newtab_start_observer_notification.js b/browser/components/tabbrowser/test/browser/tabs/browser_open_newtab_start_observer_notification.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_open_newtab_start_observer_notification.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_open_newtab_start_observer_notification.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_opened_file_tab_navigated_to_web.js b/browser/components/tabbrowser/test/browser/tabs/browser_opened_file_tab_navigated_to_web.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_opened_file_tab_navigated_to_web.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_opened_file_tab_navigated_to_web.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_origin_attrs_in_remote_type.js b/browser/components/tabbrowser/test/browser/tabs/browser_origin_attrs_in_remote_type.js
similarity index 97%
rename from browser/components/tabbrowser/test/tabs/browser_origin_attrs_in_remote_type.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_origin_attrs_in_remote_type.js
index c7f60cc8b7d1a4b35cc96e9d774d6c5766ddfeea..814ae0f47e0c28a56379a6d34308e90c29757460 100644
--- a/browser/components/tabbrowser/test/tabs/browser_origin_attrs_in_remote_type.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_origin_attrs_in_remote_type.js
@@ -7,7 +7,8 @@
 /* import-globals-from helper_origin_attrs_testing.js */
 loadTestSubscript("helper_origin_attrs_testing.js");
 
-const PATH = "browser/browser/components/tabbrowser/test/tabs/blank.html";
+const PATH =
+  "browser/browser/components/tabbrowser/test/browser/tabs/blank.html";
 
 var TEST_CASES = [
   { uri: "https://example.com/" + PATH },
diff --git a/browser/components/tabbrowser/test/tabs/browser_origin_attrs_rel.js b/browser/components/tabbrowser/test/browser/tabs/browser_origin_attrs_rel.js
similarity index 98%
rename from browser/components/tabbrowser/test/tabs/browser_origin_attrs_rel.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_origin_attrs_rel.js
index 41a7ae3eab03cdaa16b0ff6c592ede7c20d2ecef..0b046f23c91cc19e545ac3b014021a6c4ad23fb0 100644
--- a/browser/components/tabbrowser/test/tabs/browser_origin_attrs_rel.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_origin_attrs_rel.js
@@ -8,11 +8,11 @@
 loadTestSubscript("helper_origin_attrs_testing.js");
 
 const PATH =
-  "browser/browser/components/tabbrowser/test/tabs/file_rel_opener_noopener.html";
+  "browser/browser/components/tabbrowser/test/browser/tabs/file_rel_opener_noopener.html";
 const URI_EXAMPLECOM =
-  "https://example.com/browser/browser/components/tabbrowser/test/tabs/blank.html";
+  "https://example.com/browser/browser/components/tabbrowser/test/browser/tabs/blank.html";
 const URI_EXAMPLEORG =
-  "https://example.org/browser/browser/components/tabbrowser/test/tabs/blank.html";
+  "https://example.org/browser/browser/components/tabbrowser/test/browser/tabs/blank.html";
 var TEST_CASES = ["https://example.com/" + PATH, "https://example.org/" + PATH];
 // How many times we navigate (exclude going back)
 const NUM_NAVIGATIONS = 5;
diff --git a/browser/components/tabbrowser/test/tabs/browser_originalURI.js b/browser/components/tabbrowser/test/browser/tabs/browser_originalURI.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_originalURI.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_originalURI.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_overflowScroll.js b/browser/components/tabbrowser/test/browser/tabs/browser_overflowScroll.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_overflowScroll.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_overflowScroll.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_paste_event_at_middle_click_on_link.js b/browser/components/tabbrowser/test/browser/tabs/browser_paste_event_at_middle_click_on_link.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_paste_event_at_middle_click_on_link.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_paste_event_at_middle_click_on_link.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_pinnedTabs.js b/browser/components/tabbrowser/test/browser/tabs/browser_pinnedTabs.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_pinnedTabs.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_pinnedTabs.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_pinnedTabs_clickOpen.js b/browser/components/tabbrowser/test/browser/tabs/browser_pinnedTabs_clickOpen.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_pinnedTabs_clickOpen.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_pinnedTabs_clickOpen.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_pinnedTabs_closeByKeyboard.js b/browser/components/tabbrowser/test/browser/tabs/browser_pinnedTabs_closeByKeyboard.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_pinnedTabs_closeByKeyboard.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_pinnedTabs_closeByKeyboard.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_positional_attributes.js b/browser/components/tabbrowser/test/browser/tabs/browser_positional_attributes.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_positional_attributes.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_positional_attributes.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_preloadedBrowser_zoom.js b/browser/components/tabbrowser/test/browser/tabs/browser_preloadedBrowser_zoom.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_preloadedBrowser_zoom.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_preloadedBrowser_zoom.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_privilegedmozilla_process_pref.js b/browser/components/tabbrowser/test/browser/tabs/browser_privilegedmozilla_process_pref.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_privilegedmozilla_process_pref.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_privilegedmozilla_process_pref.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_progress_keyword_search_handling.js b/browser/components/tabbrowser/test/browser/tabs/browser_progress_keyword_search_handling.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_progress_keyword_search_handling.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_progress_keyword_search_handling.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_relatedTabs_reset.js b/browser/components/tabbrowser/test/browser/tabs/browser_relatedTabs_reset.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_relatedTabs_reset.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_relatedTabs_reset.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_reload_deleted_file.js b/browser/components/tabbrowser/test/browser/tabs/browser_reload_deleted_file.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_reload_deleted_file.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_reload_deleted_file.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_removeTabsToTheEnd.js b/browser/components/tabbrowser/test/browser/tabs/browser_removeTabsToTheEnd.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_removeTabsToTheEnd.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_removeTabsToTheEnd.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_removeTabsToTheStart.js b/browser/components/tabbrowser/test/browser/tabs/browser_removeTabsToTheStart.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_removeTabsToTheStart.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_removeTabsToTheStart.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_removeTabs_order.js b/browser/components/tabbrowser/test/browser/tabs/browser_removeTabs_order.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_removeTabs_order.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_removeTabs_order.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_removeTabs_skipPermitUnload.js b/browser/components/tabbrowser/test/browser/tabs/browser_removeTabs_skipPermitUnload.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_removeTabs_skipPermitUnload.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_removeTabs_skipPermitUnload.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_replacewithwindow_commands.js b/browser/components/tabbrowser/test/browser/tabs/browser_replacewithwindow_commands.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_replacewithwindow_commands.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_replacewithwindow_commands.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_switch_by_scrolling.js b/browser/components/tabbrowser/test/browser/tabs/browser_switch_by_scrolling.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_switch_by_scrolling.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_switch_by_scrolling.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabCloseProbes.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabCloseProbes.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabCloseProbes.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabCloseProbes.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabCloseSpacer.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabCloseSpacer.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabCloseSpacer.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabCloseSpacer.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabContextMenu_keyboard.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabContextMenu_keyboard.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabContextMenu_keyboard.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabContextMenu_keyboard.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabReorder.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabReorder.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabReorder.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabReorder.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabReorder_overflow.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabReorder_overflow.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabReorder_overflow.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabReorder_overflow.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabSpinnerProbe.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabSpinnerProbe.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabSpinnerProbe.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabSpinnerProbe.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabSuccessors.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabSuccessors.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabSuccessors.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabSuccessors.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_a11y_description.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_a11y_description.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_a11y_description.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_a11y_description.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_label_during_reload.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_label_during_reload.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_label_during_reload.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_label_during_reload.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_label_picture_in_picture.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_label_picture_in_picture.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_label_picture_in_picture.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_label_picture_in_picture.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_manager_close.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_manager_close.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_manager_close.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_manager_close.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_manager_drag.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_manager_drag.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_manager_drag.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_manager_drag.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_manager_keyboard_access.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_manager_keyboard_access.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_manager_keyboard_access.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_manager_keyboard_access.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_manager_visibility.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_manager_visibility.js
similarity index 95%
rename from browser/components/tabbrowser/test/tabs/browser_tab_manager_visibility.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_manager_visibility.js
index d439d5d135b0b2c09b12c2eb4aa13ff835d9d540..85cc1b7e2cce89105427e9e6afc8c3a14ee0e661 100644
--- a/browser/components/tabbrowser/test/tabs/browser_tab_manager_visibility.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_tab_manager_visibility.js
@@ -7,7 +7,7 @@
 // The hostname for the test URIs.
 const TEST_HOSTNAME = "https://example.com";
 const DUMMY_PAGE_PATH =
-  "/browser/components/tabbrowser/test/tabs/dummy_page.html";
+  "/browser/components/tabbrowser/test/browser/tabs/dummy_page.html";
 
 add_task(async function tab_manager_visibility_preference_on() {
   Services.prefs.setBoolPref("browser.tabs.tabmanager.enabled", true);
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_move_to_new_window_reload.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_move_to_new_window_reload.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_move_to_new_window_reload.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_move_to_new_window_reload.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_play.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_play.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_play.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_play.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_preview.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_preview.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_preview.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_preview.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tab_tooltips.js b/browser/components/tabbrowser/test/browser/tabs/browser_tab_tooltips.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tab_tooltips.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tab_tooltips.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabswitch_contextmenu.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabswitch_contextmenu.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabswitch_contextmenu.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabswitch_contextmenu.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabswitch_select.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabswitch_select.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabswitch_select.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabswitch_select.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabswitch_updatecommands.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabswitch_updatecommands.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabswitch_updatecommands.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabswitch_updatecommands.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_tabswitch_window_focus.js b/browser/components/tabbrowser/test/browser/tabs/browser_tabswitch_window_focus.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_tabswitch_window_focus.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_tabswitch_window_focus.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_undo_close_tabs.js b/browser/components/tabbrowser/test/browser/tabs/browser_undo_close_tabs.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_undo_close_tabs.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_undo_close_tabs.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_undo_close_tabs_at_start.js b/browser/components/tabbrowser/test/browser/tabs/browser_undo_close_tabs_at_start.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_undo_close_tabs_at_start.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_undo_close_tabs_at_start.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_viewsource_of_data_URI_in_file_process.js b/browser/components/tabbrowser/test/browser/tabs/browser_viewsource_of_data_URI_in_file_process.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_viewsource_of_data_URI_in_file_process.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_viewsource_of_data_URI_in_file_process.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_visibleTabs_bookmarkAllTabs.js b/browser/components/tabbrowser/test/browser/tabs/browser_visibleTabs_bookmarkAllTabs.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_visibleTabs_bookmarkAllTabs.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_visibleTabs_bookmarkAllTabs.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_visibleTabs_contextMenu.js b/browser/components/tabbrowser/test/browser/tabs/browser_visibleTabs_contextMenu.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/browser_visibleTabs_contextMenu.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_visibleTabs_contextMenu.js
diff --git a/browser/components/tabbrowser/test/tabs/browser_window_open_modifiers.js b/browser/components/tabbrowser/test/browser/tabs/browser_window_open_modifiers.js
similarity index 99%
rename from browser/components/tabbrowser/test/tabs/browser_window_open_modifiers.js
rename to browser/components/tabbrowser/test/browser/tabs/browser_window_open_modifiers.js
index 04d63a360d8048b614411c5d645cff708fbae64a..f49ee82d54e33bf3fd4fa90ed3c0ff1bfd04dbb0 100644
--- a/browser/components/tabbrowser/test/tabs/browser_window_open_modifiers.js
+++ b/browser/components/tabbrowser/test/browser/tabs/browser_window_open_modifiers.js
@@ -9,7 +9,7 @@ requestLongerTimeout(4);
 
 add_task(async function () {
   await BrowserTestUtils.withNewTab(
-    "https://example.com/browser/browser/components/tabbrowser/test/tabs/file_window_open.html",
+    "https://example.com/browser/browser/components/tabbrowser/test/browser/tabs/file_window_open.html",
     async function (browser) {
       const metaKey = AppConstants.platform == "macosx" ? "metaKey" : "ctrlKey";
       const normalEvent = {};
diff --git a/browser/components/tabbrowser/test/tabs/common_link_in_tab_title_and_url_prefilled.js b/browser/components/tabbrowser/test/browser/tabs/common_link_in_tab_title_and_url_prefilled.js
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/common_link_in_tab_title_and_url_prefilled.js
rename to browser/components/tabbrowser/test/browser/tabs/common_link_in_tab_title_and_url_prefilled.js
diff --git a/browser/components/tabbrowser/test/tabs/dummy_page.html b/browser/components/tabbrowser/test/browser/tabs/dummy_page.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/dummy_page.html
rename to browser/components/tabbrowser/test/browser/tabs/dummy_page.html
diff --git a/browser/components/tabbrowser/test/tabs/file_about_child.html b/browser/components/tabbrowser/test/browser/tabs/file_about_child.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/file_about_child.html
rename to browser/components/tabbrowser/test/browser/tabs/file_about_child.html
diff --git a/browser/components/tabbrowser/test/tabs/file_about_parent.html b/browser/components/tabbrowser/test/browser/tabs/file_about_parent.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/file_about_parent.html
rename to browser/components/tabbrowser/test/browser/tabs/file_about_parent.html
diff --git a/browser/components/tabbrowser/test/tabs/file_about_srcdoc.html b/browser/components/tabbrowser/test/browser/tabs/file_about_srcdoc.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/file_about_srcdoc.html
rename to browser/components/tabbrowser/test/browser/tabs/file_about_srcdoc.html
diff --git a/browser/components/tabbrowser/test/tabs/file_anchor_elements.html b/browser/components/tabbrowser/test/browser/tabs/file_anchor_elements.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/file_anchor_elements.html
rename to browser/components/tabbrowser/test/browser/tabs/file_anchor_elements.html
diff --git a/browser/components/tabbrowser/test/tabs/file_mediaPlayback.html b/browser/components/tabbrowser/test/browser/tabs/file_mediaPlayback.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/file_mediaPlayback.html
rename to browser/components/tabbrowser/test/browser/tabs/file_mediaPlayback.html
diff --git a/browser/components/tabbrowser/test/tabs/file_new_tab_page.html b/browser/components/tabbrowser/test/browser/tabs/file_new_tab_page.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/file_new_tab_page.html
rename to browser/components/tabbrowser/test/browser/tabs/file_new_tab_page.html
diff --git a/browser/components/tabbrowser/test/tabs/file_observe_height_changes.html b/browser/components/tabbrowser/test/browser/tabs/file_observe_height_changes.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/file_observe_height_changes.html
rename to browser/components/tabbrowser/test/browser/tabs/file_observe_height_changes.html
diff --git a/browser/components/tabbrowser/test/browser/tabs/file_rel_opener_noopener.html b/browser/components/tabbrowser/test/browser/tabs/file_rel_opener_noopener.html
new file mode 100644
index 0000000000000000000000000000000000000000..0a1a0655b7942f01cb34735b73cfb3e764454af9
--- /dev/null
+++ b/browser/components/tabbrowser/test/browser/tabs/file_rel_opener_noopener.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+  </head>
+  <body>
+    <a target="_blank" rel="noopener" href="https://example.com/browser/browser/components/tabbrowser/test/browser/tabs/blank.html" id="link_noopener_examplecom">Go to example.com</a>
+    <a target="_blank" rel="opener" href="https://example.com/browser/browser/components/tabbrowser/test/browser/tabs/blank.html" id="link_opener_examplecom">Go to example.com</a>
+    <a target="_blank" rel="noopener" href="https://example.org/browser/browser/components/tabbrowser/test/browser/tabs/blank.html" id="link_noopener_exampleorg">Go to example.org</a>
+    <a target="_blank" rel="opener" href="https://example.org/browser/browser/components/tabbrowser/test/browser/tabs/blank.html" id="link_opener_exampleorg">Go to example.org</a>
+  </body>
+</html>
diff --git a/browser/components/tabbrowser/test/tabs/file_window_open.html b/browser/components/tabbrowser/test/browser/tabs/file_window_open.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/file_window_open.html
rename to browser/components/tabbrowser/test/browser/tabs/file_window_open.html
diff --git a/browser/components/tabbrowser/test/tabs/head.js b/browser/components/tabbrowser/test/browser/tabs/head.js
similarity index 99%
rename from browser/components/tabbrowser/test/tabs/head.js
rename to browser/components/tabbrowser/test/browser/tabs/head.js
index e0a1b9cc13bd2bb4c00122566e21919d128757ce..6b1b32690594b95ff4f44b606e95f3e9dbbe845f 100644
--- a/browser/components/tabbrowser/test/tabs/head.js
+++ b/browser/components/tabbrowser/test/browser/tabs/head.js
@@ -50,7 +50,7 @@ async function addTabTo(
 
 async function addMediaTab() {
   const PAGE =
-    "https://example.com/browser/browser/components/tabbrowser/test/tabs/file_mediaPlayback.html";
+    "https://example.com/browser/browser/components/tabbrowser/test/browser/tabs/file_mediaPlayback.html";
   const tab = BrowserTestUtils.addTab(gBrowser, PAGE, { skipAnimation: true });
   const browser = gBrowser.getBrowserForTab(tab);
   await BrowserTestUtils.browserLoaded(browser);
diff --git a/browser/components/tabbrowser/test/tabs/helper_origin_attrs_testing.js b/browser/components/tabbrowser/test/browser/tabs/helper_origin_attrs_testing.js
similarity index 96%
rename from browser/components/tabbrowser/test/tabs/helper_origin_attrs_testing.js
rename to browser/components/tabbrowser/test/browser/tabs/helper_origin_attrs_testing.js
index 0b3d2a9c0c2fec802847f4204cc5358f0e5958eb..b8c70e547a47b8caece7e71ebc9ce20a78099fc8 100644
--- a/browser/components/tabbrowser/test/tabs/helper_origin_attrs_testing.js
+++ b/browser/components/tabbrowser/test/browser/tabs/helper_origin_attrs_testing.js
@@ -133,8 +133,8 @@ function initXulFrameLoaderCreatedCounter(aXulFrameLoaderCreatedListenerInfo) {
 }
 
 // Expected remote types for the following tests:
-// browser/components/tabbrowser/test/tabs/browser_navigate_through_urls_origin_attributes.js
-// browser/components/tabbrowser/test/tabs/browser_origin_attrs_in_remote_type.js
+// browser/components/tabbrowser/test/browser/tabs/browser_navigate_through_urls_origin_attributes.js
+// browser/components/tabbrowser/test/browser/tabs/browser_origin_attrs_in_remote_type.js
 function getExpectedRemoteTypes(gFissionBrowser, numPagesOpen) {
   var remoteTypes;
   if (gFissionBrowser) {
diff --git a/browser/components/tabbrowser/test/tabs/link_in_tab_title_and_url_prefilled.html b/browser/components/tabbrowser/test/browser/tabs/link_in_tab_title_and_url_prefilled.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/link_in_tab_title_and_url_prefilled.html
rename to browser/components/tabbrowser/test/browser/tabs/link_in_tab_title_and_url_prefilled.html
diff --git a/browser/components/tabbrowser/test/tabs/open_window_in_new_tab.html b/browser/components/tabbrowser/test/browser/tabs/open_window_in_new_tab.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/open_window_in_new_tab.html
rename to browser/components/tabbrowser/test/browser/tabs/open_window_in_new_tab.html
diff --git a/browser/components/tabbrowser/test/tabs/page_with_iframe.html b/browser/components/tabbrowser/test/browser/tabs/page_with_iframe.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/page_with_iframe.html
rename to browser/components/tabbrowser/test/browser/tabs/page_with_iframe.html
diff --git a/browser/components/tabbrowser/test/tabs/redirect_via_header.html b/browser/components/tabbrowser/test/browser/tabs/redirect_via_header.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/redirect_via_header.html
rename to browser/components/tabbrowser/test/browser/tabs/redirect_via_header.html
diff --git a/browser/components/tabbrowser/test/tabs/redirect_via_header.html^headers^ b/browser/components/tabbrowser/test/browser/tabs/redirect_via_header.html^headers^
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/redirect_via_header.html^headers^
rename to browser/components/tabbrowser/test/browser/tabs/redirect_via_header.html^headers^
diff --git a/browser/components/tabbrowser/test/tabs/redirect_via_meta_tag.html b/browser/components/tabbrowser/test/browser/tabs/redirect_via_meta_tag.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/redirect_via_meta_tag.html
rename to browser/components/tabbrowser/test/browser/tabs/redirect_via_meta_tag.html
diff --git a/browser/components/tabbrowser/test/tabs/request-timeout.sjs b/browser/components/tabbrowser/test/browser/tabs/request-timeout.sjs
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/request-timeout.sjs
rename to browser/components/tabbrowser/test/browser/tabs/request-timeout.sjs
diff --git a/browser/components/tabbrowser/test/tabs/tab_that_closes.html b/browser/components/tabbrowser/test/browser/tabs/tab_that_closes.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/tab_that_closes.html
rename to browser/components/tabbrowser/test/browser/tabs/tab_that_closes.html
diff --git a/browser/components/tabbrowser/test/tabs/test_bug1358314.html b/browser/components/tabbrowser/test/browser/tabs/test_bug1358314.html
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/test_bug1358314.html
rename to browser/components/tabbrowser/test/browser/tabs/test_bug1358314.html
diff --git a/browser/components/tabbrowser/test/tabs/test_process_flags_chrome.html b/browser/components/tabbrowser/test/browser/tabs/test_process_flags_chrome.html
similarity index 50%
rename from browser/components/tabbrowser/test/tabs/test_process_flags_chrome.html
rename to browser/components/tabbrowser/test/browser/tabs/test_process_flags_chrome.html
index 6c68bfc6d3e7686d47c9ae74ca15781f2bda6b88..e2236f4ac053546cbf135bf865ad79ce5c604508 100644
--- a/browser/components/tabbrowser/test/tabs/test_process_flags_chrome.html
+++ b/browser/components/tabbrowser/test/browser/tabs/test_process_flags_chrome.html
@@ -3,8 +3,8 @@
 <html>
 <body>
 <p>chrome: test page</p>
-<p><a href="chrome://mochitests/content/browser/browser/components/tabbrowser/test/tabs/test_process_flags_chrome.html">chrome</a></p>
-<p><a href="chrome://mochitests-any/content/browser/browser/components/tabbrowser/test/tabs/test_process_flags_chrome.html">canremote</a></p>
-<p><a href="chrome://mochitests-content/content/browser/browser/components/tabbrowser/test/tabs/test_process_flags_chrome.html">mustremote</a></p>
+<p><a href="chrome://mochitests/content/browser/browser/components/tabbrowser/test/browser/tabs/test_process_flags_chrome.html">chrome</a></p>
+<p><a href="chrome://mochitests-any/content/browser/browser/components/tabbrowser/test/browser/tabs/test_process_flags_chrome.html">canremote</a></p>
+<p><a href="chrome://mochitests-content/content/browser/browser/components/tabbrowser/test/browser/tabs/test_process_flags_chrome.html">mustremote</a></p>
 </body>
 </html>
diff --git a/browser/components/tabbrowser/test/tabs/wait-a-bit.sjs b/browser/components/tabbrowser/test/browser/tabs/wait-a-bit.sjs
similarity index 100%
rename from browser/components/tabbrowser/test/tabs/wait-a-bit.sjs
rename to browser/components/tabbrowser/test/browser/tabs/wait-a-bit.sjs
diff --git a/browser/components/tabbrowser/test/tabs/file_rel_opener_noopener.html b/browser/components/tabbrowser/test/tabs/file_rel_opener_noopener.html
deleted file mode 100644
index c8fc18f189cfe10d2c9a0151f078400e4d2d40d4..0000000000000000000000000000000000000000
--- a/browser/components/tabbrowser/test/tabs/file_rel_opener_noopener.html
+++ /dev/null
@@ -1,12 +0,0 @@
-<!DOCTYPE html>
-<html>
-  <head>
-    <meta charset="utf-8">
-  </head>
-  <body>
-    <a target="_blank" rel="noopener" href="https://example.com/browser/browser/components/tabbrowser/test/tabs/blank.html" id="link_noopener_examplecom">Go to example.com</a>
-    <a target="_blank" rel="opener" href="https://example.com/browser/browser/components/tabbrowser/test/tabs/blank.html" id="link_opener_examplecom">Go to example.com</a>
-    <a target="_blank" rel="noopener" href="https://example.org/browser/browser/components/tabbrowser/test/tabs/blank.html" id="link_noopener_exampleorg">Go to example.org</a>
-    <a target="_blank" rel="opener" href="https://example.org/browser/browser/components/tabbrowser/test/tabs/blank.html" id="link_opener_exampleorg">Go to example.org</a>
-  </body>
-</html>
diff --git a/browser/modules/test/browser/browser.toml b/browser/modules/test/browser/browser.toml
index 82c3fbfd87eb98f0d1d979d3426c61457b64f0ed..9662dc087e48a39b17f87b2006e6c2544658a0c9 100644
--- a/browser/modules/test/browser/browser.toml
+++ b/browser/modules/test/browser/browser.toml
@@ -32,8 +32,8 @@ https_first_disabled = true
 ["browser_TabUnloader.js"]
 support-files = [
   "file_webrtc.html",
-  "../../../components/tabbrowser/test/tabs/dummy_page.html",
-  "../../../components/tabbrowser/test/tabs/file_mediaPlayback.html",
+  "../../../components/tabbrowser/test/browser/tabs/dummy_page.html",
+  "../../../components/tabbrowser/test/browser/tabs/file_mediaPlayback.html",
   "../../../base/content/test/general/audio.ogg",
 ]
 skip-if = [
diff --git a/taskcluster/test/data/bugbug-push-schedules.json b/taskcluster/test/data/bugbug-push-schedules.json
index 47f24b07c2df332635b0c70392c13550bbf80bab..e07a7d0d605b6eadf38eb004b6d26aea09ce6bc2 100644
--- a/taskcluster/test/data/bugbug-push-schedules.json
+++ b/taskcluster/test/data/bugbug-push-schedules.json
@@ -275,7 +275,7 @@
     "browser/components/ssb/tests/browser/browser.toml": [
       "test-linux1804-64/debug-*-spi-nw"
     ],
-    "browser/components/tabbrowser/test/tabs/browser.toml": [
+    "browser/components/tabbrowser/test/browser/tabs/browser.toml": [
       "test-windows11-64-2009-asan/opt-*",
       "test-linux1804-64/debug-*",
       "test-windows11-64-2009/opt-*"
@@ -1967,7 +1967,7 @@
     "browser/components/shell/test/browser.toml": 0.95,
     "browser/components/shell/test/chrome.toml": 0.79,
     "browser/components/ssb/tests/browser/browser.toml": 0.81,
-    "browser/components/tabbrowser/test/tabs/browser.toml": 0.81,
+    "browser/components/tabbrowser/test/browser/tabs/browser.toml": 0.81,
     "browser/components/tests/browser/browser.toml": 0.67,
     "browser/components/tests/browser/whats_new_page/browser.toml": 0.56,
     "browser/components/tests/unit/xpcshell.toml": 0.82,
diff --git a/tools/lint/rejected-words.yml b/tools/lint/rejected-words.yml
index 66e2b747be866d9742360959253b006b06386068..76677bee842c908023eb9a9f1c7bc26bc817f2f5 100644
--- a/tools/lint/rejected-words.yml
+++ b/tools/lint/rejected-words.yml
@@ -55,7 +55,7 @@ avoid-blacklist-and-whitelist:
         - browser/components/resistfingerprinting/test/mochitest/test_bug1354633_media_error.html
         - browser/components/safebrowsing/content/test/browser_whitelisted.js
         - browser/components/sessionstore/test/browser_crashedTabs.js
-        - browser/components/tabbrowser/test/tabs/browser_new_file_whitelisted_http_tab.js
+        - browser/components/tabbrowser/test/browser/tabs/browser_new_file_whitelisted_http_tab.js
         - browser/components/uitour/UITourChild.sys.mjs
         - browser/components/urlbar/tests/browser/browser_searchSingleWordNotification.js
         - browser/components/urlbar/tests/browser/browser_UrlbarInput_trimURLs.js