--- a/servo/components/style/properties/longhand/pointing.mako.rs
+++ b/servo/components/style/properties/longhand/pointing.mako.rs
@@ -177,8 +177,19 @@
     "ColorOrAuto",
     "Either::Second(Auto)",
     spec="https://drafts.csswg.org/css-ui/#caret-color",
     animation_value_type="Either<AnimatedColor, Auto>",
     boxed=True,
     ignored_when_colors_disabled=True,
     products="gecko",
 )}
+
+${helpers.predefined_type(
+    "-moz-font-smoothing-background-color",
+    "RGBAColor",
+    "RGBA::transparent()",
+    animation_value_type="AnimatedRGBA",
+    products="gecko",
+    gecko_ffi_name="mFontSmoothingBackgroundColor",
+    internal=True,
+    spec="None (Nonstandard internal property)"
+)}