1 files changed, 0 insertions, 6 deletions
diff --git a/layout/style/res/ua.css b/layout/style/res/ua.css
index a8425d472a..ab51f67c53 100644
--- a/layout/style/res/ua.css
+++ b/layout/style/res/ua.css
@@ -474,9 +474,3 @@ div:-moz-native-anonymous.moz-custom-content-container {
   width: 100%;
   height: 100%;
 }
-
-/* Shadow DOM v1
- * https://drafts.csswg.org/css-scoping/#slots-in-shadow-tree */
-slot {
-  display: contents;
-}
-\ No newline at end of file