--- a/servo/components/style/properties/longhand/box.mako.rs
+++ b/servo/components/style/properties/longhand/box.mako.rs
@@ -576,16 +576,18 @@
                             -moz-mac-vibrancy-light -moz-mac-vibrant-titlebar-light -moz-mac-vibrant-titlebar-dark
                             -moz-win-borderless-glass -moz-win-browsertabbar-toolbox
                             -moz-win-communications-toolbox -moz-win-exclude-glass -moz-win-glass -moz-win-media-toolbox
                             -moz-window-button-box -moz-window-button-box-maximized -moz-window-button-close
                             -moz-window-button-maximize -moz-window-button-minimize -moz-window-button-restore
                             -moz-window-frame-bottom -moz-window-frame-left -moz-window-frame-right -moz-window-titlebar
                             -moz-window-titlebar-maximized
                          """,
+                         alias="-webkit-appearance",
+                         gecko_pref="layout.css.webkit-appearance.enabled",
                          gecko_ffi_name="mAppearance",
                          gecko_constant_prefix="ThemeWidgetType_NS_THEME",
                          products="gecko",
                          spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-appearance)",
                          animation_value_type="discrete")}
 
 ${helpers.predefined_type("-moz-binding", "UrlOrNone", "Either::Second(None_)",
                           products="gecko",