--- a/browser/base/content/browser.xul
+++ b/browser/base/content/browser.xul
@@ -612,17 +612,16 @@
                      class="toolbarbutton-1 chromeclass-toolbar-additional tabs-alltabs-button"
                      type="menu"
                      label="&listAllTabs.label;"
                      tooltiptext="&listAllTabs.label;"
                      removable="false">
         <menupopup id="alltabs-popup"
                    position="after_end">
           <menuitem id="alltabs_undoCloseTab"
-                    class="menuitem-iconic"
                     key="key_undoCloseTab"
                     label="&undoCloseTab.label;"
                     observes="History:UndoCloseTab"/>
           <menuseparator id="alltabs-popup-separator-1"/>
           <menu id="alltabs_containersTab"
                 label="&newUserContext.label;">
             <menupopup id="alltabs_containersMenuTab" />
           </menu>

--- a/browser/themes/linux/browser.css
+++ b/browser/themes/linux/browser.css
@@ -533,21 +533,16 @@ menuitem.bookmark-item {
   transition-delay: 100s;
 }
 
 @conditionalForwardWithUrlbar@:not(:hover) > #forward-button[disabled] {
   /* when not hovered anymore, trigger a new transition to hide the forward button immediately */
   margin-left: calc(-0.01px - var(--forwardbutton-width) - var(--backbutton-urlbar-overlap));
 }
 
-/* undo close tab menu item */
-#alltabs_undoCloseTab {
-  list-style-image: url(chrome://browser/skin/undoCloseTab.png);
-}
-
 .unified-nav-back[_moz-menuactive] {
   list-style-image: url("moz-icon://stock/gtk-go-back-ltr?size=menu") !important;
 }
 .unified-nav-back[_moz-menuactive]:-moz-locale-dir(rtl) {
   list-style-image: url("moz-icon://stock/gtk-go-back-rtl?size=menu") !important;
 }
 .unified-nav-forward[_moz-menuactive] {
   list-style-image: url("moz-icon://stock/gtk-go-forward-ltr?size=menu") !important;

--- a/browser/themes/osx/browser.css
+++ b/browser/themes/osx/browser.css
@@ -1350,30 +1350,16 @@ toolbar .toolbarbutton-1 > .toolbarbutto
   list-style-image: url("chrome://browser/skin/menu-back.png") !important;
 }
 
 .unified-nav-forward[_moz-menuactive]:-moz-locale-dir(ltr),
 .unified-nav-back[_moz-menuactive]:-moz-locale-dir(rtl) {
   list-style-image: url("chrome://browser/skin/menu-forward.png") !important;
 }
 
-/* undo close tab menu item */
-#alltabs_undoCloseTab {
-  list-style-image: url(chrome://browser/skin/undoCloseTab.png);
-}
-
-@media (min-resolution: 2dppx) {
-  #alltabs_undoCloseTab {
-    list-style-image: url(chrome://browser/skin/undoCloseTab@2x.png);
-  }
-  #alltabs_undoCloseTab > .toolbarbutton-icon {
-    width: 16px;
-  }
-}
-
 #cut-button {
   margin-inline-end: 0;
 }
 
 #edit-controls[cui-areatype="toolbar"] > #cut-button {
   border-inline-end: 0;
 }
 

--- a/browser/themes/shared/jar.inc.mn
+++ b/browser/themes/shared/jar.inc.mn
@@ -105,18 +105,16 @@
   skin/classic/browser/tabbrowser/tab-audio.svg                (../shared/tabbrowser/tab-audio.svg)
   skin/classic/browser/tabbrowser/tab-audio-small.svg          (../shared/tabbrowser/tab-audio-small.svg)
   skin/classic/browser/tabbrowser/tab-overflow-indicator.png   (../shared/tabbrowser/tab-overflow-indicator.png)
   skin/classic/browser/toolbarbutton-dropdown-arrow.png        (../shared/toolbarbutton-dropdown-arrow.png)
   skin/classic/browser/translating-16.png                      (../shared/translation/translating-16.png)
   skin/classic/browser/translating-16@2x.png                   (../shared/translation/translating-16@2x.png)
   skin/classic/browser/translation-16.png                      (../shared/translation/translation-16.png)
   skin/classic/browser/translation-16@2x.png                   (../shared/translation/translation-16@2x.png)
-  skin/classic/browser/undoCloseTab.png                        (../shared/undoCloseTab.png)
-  skin/classic/browser/undoCloseTab@2x.png                     (../shared/undoCloseTab@2x.png)
   skin/classic/browser/update-badge.svg                        (../shared/update-badge.svg)
   skin/classic/browser/update-badge-failed.svg                 (../shared/update-badge-failed.svg)
   skin/classic/browser/warning.svg                             (../shared/warning.svg)
   skin/classic/browser/warning-white.svg                       (../shared/warning-white.svg)
   skin/classic/browser/cert-error.svg                          (../shared/incontent-icons/cert-error.svg)
   skin/classic/browser/wifi.svg                                (../shared/incontent-icons/wifi.svg)
   skin/classic/browser/session-restore.svg                     (../shared/incontent-icons/session-restore.svg)
   skin/classic/browser/tab-crashed.svg                         (../shared/incontent-icons/tab-crashed.svg)

deleted file mode 100644
index 1d629c82c5818662686be1164bdc8965684b0964..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

deleted file mode 100644
index 4854c5681dafc13817511d3c5dbe343dab332810..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -916,30 +916,16 @@ toolbar[brighttext] .toolbarbutton-1 > .
   list-style-image: url("chrome://browser/skin/menu-back.png") !important;
 }
 
 .unified-nav-forward[_moz-menuactive]:-moz-locale-dir(ltr),
 .unified-nav-back[_moz-menuactive]:-moz-locale-dir(rtl) {
   list-style-image: url("chrome://browser/skin/menu-forward.png") !important;
 }
 
-/* undo close tab menu item */
-#alltabs_undoCloseTab {
-  list-style-image: url(chrome://browser/skin/undoCloseTab.png);
-}
-
-@media (min-resolution: 1.1dppx) {
-  #alltabs_undoCloseTab {
-    list-style-image: url(chrome://browser/skin/undoCloseTab@2x.png);
-  }
-  #alltabs_undoCloseTab > .toolbarbutton-icon {
-    width: 16px;
-  }
-}
-
 /* zoom control text (reset) button special case: */
 
 #nav-bar #zoom-reset-button > .toolbarbutton-text {
   /* To make this line up with the icons, it needs the same height (18px) +
    * padding (2 * 2px) + border (2 * 1px), but as a minimum because otherwise
    * increase in text sizes would break things...
    */
   min-height: 24px;