diff --git a/doc/src/sgml/extend.sgml b/doc/src/sgml/extend.sgml
index 63c5ec6d1eb..997b98db7bc 100644
--- a/doc/src/sgml/extend.sgml
+++ b/doc/src/sgml/extend.sgml
@@ -610,7 +610,12 @@ RETURNS anycompatible AS ...
     such objects, if it does so they will not be tracked as part of the
     extension.)  Also notice that while a table can be a member of an
     extension, its subsidiary objects such as indexes are not directly
-    considered members of the extension.
+    considered members of the extension. Consequently, such objects added
+    manually to extension tables will not be preserved by
+    <application>pg_dump</application>.
+   </para>
+
+   <para>
     Another important point is that schemas can belong to extensions, but not
     vice versa: an extension as such has an unqualified name and does not
     exist <quote>within</quote> any schema.  The extension's member objects,
diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml
index d7595a7e546..d63c5d4ec1c 100644
--- a/doc/src/sgml/ref/pg_dump.sgml
+++ b/doc/src/sgml/ref/pg_dump.sgml
@@ -1671,6 +1671,11 @@ CREATE DATABASE foo WITH TEMPLATE template0;
 </programlisting>
   </para>
 
+  <para>
+   Objects manually added to extension tables (such as indexes or constraints)
+   are not preserved by <application>pg_dump</application>.
+  </para>
+
   <para>
    When a dump without schema is chosen and the option <option>--disable-triggers</option>
    is used, <application>pg_dump</application> emits commands