diff --git a/index.bs b/index.bs
index cf7a4c10d..9a6f99997 100644
--- a/index.bs
+++ b/index.bs
@@ -1061,8 +1061,8 @@ optionally evidence of [=user consent=] to a specific transaction.
     interface AuthenticatorAssertionResponse : AuthenticatorResponse {
         [SameObject] readonly attribute ArrayBuffer      authenticatorData;
         [SameObject] readonly attribute ArrayBuffer      signature;
-        [SameObject] readonly attribute DOMString	 userId;
-        };
+        [SameObject] readonly attribute DOMString        userId;
+    };
 </pre>
 <div dfn-type="attribute" dfn-for="AuthenticatorAssertionResponse">
     :   {{AuthenticatorResponse/clientDataJSON}}