diff --git a/spec/registry.dtd b/spec/registry.dtd
index 8abbbc6e6e..9f9cb574be 100644
--- a/spec/registry.dtd
+++ b/spec/registry.dtd
@@ -1,3 +1,7 @@
+<!-- 
+     This DTD is not part of the LDML45 Tech Preview of MessageFormat 2.
+     Comments on this DTD are welcome. 
+-->
 <!ELEMENT registry (function|validationRule)*>
 <!ATTLIST registry
     xml:lang       NMTOKEN  #IMPLIED
diff --git a/spec/registry.xml b/spec/registry.xml
index 15f8278baf..659c6e1efd 100644
--- a/spec/registry.xml
+++ b/spec/registry.xml
@@ -1,5 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <?xml-model href="registry.dtd" type="application/xml-dtd"?>
+<!--
+     This registry is not part of the LDML45 Tech Preview of MessageFormat 2.
+     Comments on the contents of this registry are welcome as we seek to 
+     finalize the registry descriptions as part of the stable release
+     in LDML46.
+-->
 <registry xml:lang="en">
   <!-- All regex here are to be seen as provisory. See issue #422. -->
   <validationRule id="anyNumber" regex="-?(0|([1-9]\d*))(\.\d*)?([eE][-+]?\d+)?"/>