Index: trunk/resources/data/validator/highway.mapcss
===================================================================
--- trunk/resources/data/validator/highway.mapcss	(revision 18523)
+++ trunk/resources/data/validator/highway.mapcss	(revision 18552)
@@ -208,2 +208,10 @@
   assertNoMatch: "way highway=trunk";
 }
+
+/* #21396 comment 39 */
+*[surface=~/^paving_stones:(\d+)$/] {
+  throwWarning: tr("{0} with trailing number", "paving_stones");
+  group: tr("questionable value (ending with a number)");
+  suggestAlternative: "paving_stones:length";
+  suggestAlternative: "paving_stones:width";
+}