Remove OLD stuff to make the file much more clean

chrome/multi-row_tabs.css

@@ -0,0 +1,71 @@
+/* Makes tabs to appear on multiple lines */
+/* Tab reordering will not work and can't be made to work */
+/* You can use multi-row_tabs_window_control_patch.css to move window controls to nav-bar*/
+
+/* It's recommended to move tabs new-tab-button outside tabs toolbar */
+
+/* Change the --multirow-n-rows to change maximum number of rows before the rows will start to scroll  */
+/* This maximum visible rows won't work before Fx66 */
+/* So this setting does nothing on Fx65 and all tab rows will be shown */
+:root{
+    --multirow-n-rows: 3;
+    --multirow-tab-min-width: 100px;
+    --multirow-tab-dynamic-width: 1; /* Change to 0 for fixed-width tabs using the above width. */
+}
+
+/* Scrollbar can't be clicked but the rows can be scrolled with mouse wheel */
+/* Uncomment the next line if you want to be able to use the scrollbar with mouse clicks */
+
+/* #tabbrowser-arrowscrollbox{ -moz-window-dragging: no-drag } */
+
+/* Uncommenting the above makes you unable to drag the window from empty space in the tab strip but normal draggable spaces will continue to work */
+
+#tabbrowser-tabs{
+  min-height: unset !important;
+  padding-inline-start: 0px !important
+}
+
+@-moz-document url(chrome://browser/content/browser.xhtml){
+  #scrollbutton-up~spacer,
+  #scrollbutton-up,
+  #scrollbutton-down{ display: var(--scrollbutton-display-model,initial) }
+
+  scrollbox[part][orient="horizontal"]{
+    display: flex;
+    flex-wrap: wrap;
+    overflow-y: auto;
+    max-height: calc(var(--tab-min-height) * var(--multirow-n-rows));
+    scrollbar-color: currentColor transparent;
+    scrollbar-width: thin;
+  }
+}
+
+#tabbrowser-arrowscrollbox{
+  overflow: -moz-hidden-unscrollable;
+  display: block;
+  --scrollbutton-display-model: none;
+}
+
+.tabbrowser-tab{ height: var(--tab-min-height); }
+
+#tabbrowser-tabs .tabbrowser-tab[pinned]{
+  position: static !important;
+  margin-inline-start: 0px !important;
+}
+
+.tabbrowser-tab[fadein]:not([pinned]){
+  min-width: var(--multirow-tab-min-width) !important;
+  flex-grow: var(--multirow-tab-dynamic-width);
+  /*
+  Uncomment to enable full-width tabs, also makes tab dragging a tiny bit more sensible
+  Don't set to none or you'll see errors in console when closing tabs
+  */
+  /*max-width: 100vw !important;*/
+}
+
+.tabbrowser-tab > stack{ width: 100%; height: 100% }
+
+#alltabs-button,
+:root:not([customizing]) #TabsToolbar #new-tab-button,
+#tabbrowser-tabs spacer,
+.tabbrowser-tab::after{ display: none !important }