--- a/browser/themes/shared/notification-icons.inc.css
+++ b/browser/themes/shared/notification-icons.inc.css
@@ -114,19 +114,16 @@
 }
 
 .midi-icon,
 .midi-sysex-icon,
 .popup-notification-icon[popupid="midi"],
 .popup-notification-icon[popupid="midi-sysex"] {
   list-style-image: url(chrome://browser/skin/notification-icons/midi.svg);
 }
-{
-  list-style-image: url(chrome://browser/skin/notification-icons/midi.svg);
-}
 
 #canvas-notification-icon,
 .popup-notification-icon[popupid="canvas-permissions-prompt"],
 .canvas-icon {
   list-style-image: url(chrome://browser/skin/notification-icons/canvas.svg);
 }
 
 .canvas-icon.blocked-permission-icon {