diff --git a/index.bs b/index.bs
index bb4e98f7f..157ecd3e4 100644
--- a/index.bs
+++ b/index.bs
@@ -6794,7 +6794,10 @@ This [=client extension|client=] [=registration extension=] and [=authentication
     </xmp>
 
 : Client extension processing
-::  None, other than to report on credential properties in the output.
+::  [=map/Set=] <code>[=credentialCreationData/clientExtensionResults=]["{{AuthenticationExtensionsClientOutputs/credProps}}"]["rk"]</code>
+    to the value of the |requireResidentKey| parameter that was used in the
+    <a href='#CreateCred-InvokeAuthnrMakeCred'>invocation</a> of the [=authenticatorMakeCredential=]
+    operation.
 
 : Client extension output
 ::  <xmp class="idl">