diff --git a/components/style/gecko/media_features.rs b/components/style/gecko/media_features.rs
index f44fd788b00..778a57cd95d 100644
--- a/components/style/gecko/media_features.rs
+++ b/components/style/gecko/media_features.rs
@@ -585,7 +585,7 @@ macro_rules! bool_pref_feature {
 /// to support new types in these entries and (2) ensuring that either
 /// nsPresContext::MediaFeatureValuesChanged is called when the value that
 /// would be returned by the evaluator function could change.
-pub static MEDIA_FEATURES: [QueryFeatureDescription; 62] = [
+pub static MEDIA_FEATURES: [QueryFeatureDescription; 63] = [
     feature!(
         atom!("width"),
         AllowsRanges::Yes,
@@ -876,6 +876,7 @@ pub static MEDIA_FEATURES: [QueryFeatureDescription; 62] = [
         GTKCSDReversedPlacement
     ),
     lnf_int_feature!(atom!("-moz-system-dark-theme"), SystemUsesDarkTheme),
+    lnf_int_feature!(atom!("-moz-panel-animations"), PanelAnimations),
     bool_pref_feature!(
         atom!("-moz-box-flexbox-emulation"),
         "layout.css.moz-box-flexbox-emulation.enabled"