diff --git a/components/style/properties/longhand/effects.mako.rs b/components/style/properties/longhand/effects.mako.rs
index eff56c05a60..4ad6e99cda9 100644
--- a/components/style/properties/longhand/effects.mako.rs
+++ b/components/style/properties/longhand/effects.mako.rs
@@ -12,7 +12,8 @@ ${helpers.predefined_type("opacity",
                           "1.0",
                           animatable=True)}
 
-<%helpers:vector_longhand name="box-shadow" allow_empty="True" animatable="True">
+<%helpers:vector_longhand name="box-shadow" allow_empty="True" animatable="True"
+                          spec="https://drafts.csswg.org/css-backgrounds/#box-shadow">
     use cssparser;
     use std::fmt;
     use style_traits::ToCss;
@@ -74,7 +75,8 @@ ${helpers.predefined_type("opacity",
 </%helpers:vector_longhand>
 
 // FIXME: This prop should be animatable
-<%helpers:longhand name="clip" products="servo" animatable="False">
+<%helpers:longhand name="clip" products="servo" animatable="False"
+                   spec="https://drafts.fxtf.org/css-masking/#clip-property">
     use std::fmt;
     use style_traits::ToCss;
     use values::HasViewportPercentage;
@@ -287,7 +289,8 @@ ${helpers.predefined_type("opacity",
 </%helpers:longhand>
 
 // FIXME: This prop should be animatable
-<%helpers:longhand name="filter" animatable="False">
+<%helpers:longhand name="filter" animatable="False"
+                   spec="https://drafts.fxtf.org/filters/#propdef-filter">
     //pub use self::computed_value::T as SpecifiedValue;
     use cssparser;
     use std::fmt;
@@ -694,4 +697,5 @@ ${helpers.single_keyword("mix-blend-mode",
                          """normal multiply screen overlay darken lighten color-dodge
                             color-burn hard-light soft-light difference exclusion hue
                             saturation color luminosity""", gecko_constant_prefix="NS_STYLE_BLEND",
-                         animatable=False)}
+                         animatable=False,
+                         spec="https://drafts.fxtf.org/compositing/#propdef-mix-blend-mode")}