diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 2713883..7d1ee4e 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -406,26 +406,23 @@
 
    <para>
     The reason that periodic vacuuming solves the problem is that
-    <command>VACUUM</> will mark rows as <emphasis>frozen</>, indicating that
+    <command>VACUUM</> will mark rows as <emphasis>frozen</> (by setting appropriate hint bits), indicating that
     they were inserted by a transaction which committed sufficiently far in
     the past that the effects of the inserting transaction is certain to be
     visible, from an MVCC perspective, to all current and future transactions.
-    <productname>PostgreSQL</> reserves a special XID,
-    <literal>FrozenTransactionId</>, which does not follow the normal XID
-    comparison rules and is always considered older
-    than every normal XID. Normal XIDs are
+    Usually XIDs are
     compared using modulo-2<superscript>32</> arithmetic. This means
-    that for every normal XID, there are two billion XIDs that are
+    that for every XID, there are two billion XIDs that are
     <quote>older</> and two billion that are <quote>newer</>; another
-    way to say it is that the normal XID space is circular with no
+    way to say it is that the XID space is circular with no
     endpoint. Therefore, once a row version has been created with a particular
-    normal XID, the row version will appear to be <quote>in the past</> for
-    the next two billion transactions, no matter which normal XID we are
-    talking about. If the row version still exists after more than two billion
+    XID, the row version will appear to be <quote>in the past</> for
+    the next two billion transactions.
+    If the row version still exists after more than two billion
     transactions, it will suddenly appear to be in the future. To
-    prevent this, frozen row versions are treated as if the inserting XID were
-    <literal>FrozenTransactionId</>, so that they will appear to be
-    <quote>in the past</> to all normal transactions regardless of wraparound
+    prevent this, usual visibility rules are not applied to frozen row versions.
+    Instead they are considered to be
+    <quote>in the past</> to all transactions regardless of wraparound
     issues, and so such row versions will be valid until deleted, no matter
     how long that is.
    </para>