diff --git a/components/style/properties/longhands/background.mako.rs b/components/style/properties/longhands/background.mako.rs
index 1cbf601ad5d..76b71b12cd0 100644
--- a/components/style/properties/longhands/background.mako.rs
+++ b/components/style/properties/longhands/background.mako.rs
@@ -111,5 +111,6 @@ ${helpers.single_keyword(
     vector=True,
     engines="gecko",
     animation_value_type="discrete",
+    gecko_inexhaustive=True,
     spec="https://drafts.fxtf.org/compositing/#background-blend-mode",
 )}
diff --git a/components/style/properties/longhands/effects.mako.rs b/components/style/properties/longhands/effects.mako.rs
index 5470c74d47c..1860f4b1791 100644
--- a/components/style/properties/longhands/effects.mako.rs
+++ b/components/style/properties/longhands/effects.mako.rs
@@ -78,7 +78,7 @@ ${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""",
+    saturation color luminosity plus-lighter""",
     engines="gecko servo-2013 servo-2020",
     gecko_enum_prefix="StyleBlend",
     animation_value_type="discrete",