diff --git a/spec.bs b/spec.bs
index b8c0876..5b08349 100644
--- a/spec.bs
+++ b/spec.bs
@@ -369,6 +369,15 @@ below and in [[#index-defined-elsewhere]].
 
     <div class="note">TODO: Bikeshed the name.</div>
 
+    <div class="note">To quickly support an initial SPC experiment,
+    this API was designed atop existing implementations of the Payment
+    Request and Payment Handler APIs. There is now general agreement
+    to explore a design of SPC independent of Payment Request.  We
+    therefore expect (without a concrete timeline) that SPC will move
+    away from its Payment Request origins. For developers, this should
+    improve feature detection, invocation, and other aspects of the
+    API.</div>
+
 # Enrollment # {#sctn-enrollment}
 
 To enroll a user for Secure Payment Confirmation, relying parties should call