diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 14aeed30763..26984b6cba1 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -5690,6 +5690,13 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
    see <xref linkend="replication-origins"/>.
   </para>
 
+  <para>
+   Unlike most system catalogs, <structname>pg_replication_origin</structname>
+   is shared across all databases of a cluster: there is only one copy
+   of <structname>pg_replication_origin</structname> per cluster, not one per
+   database.
+  </para>
+
   <table>
 
    <title><structname>pg_replication_origin</structname> Columns</title>
@@ -6608,7 +6615,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
 
   <para>
    Unlike most system catalogs, <structname>pg_subscription</structname> is
-   shared across all databases of a cluster: There is only one copy
+   shared across all databases of a cluster: there is only one copy
    of <structname>pg_subscription</structname> per cluster, not one per
    database.
   </para>
diff --git a/src/backend/utils/mmgr/README b/src/backend/utils/mmgr/README
index a42e568d5c9..7e6541d0dee 100644
--- a/src/backend/utils/mmgr/README
+++ b/src/backend/utils/mmgr/README
@@ -401,7 +401,7 @@ GetMemoryChunkContext())
 
 and then invoke the corresponding method for the context
 
-    context->methods->free_p(p);
+    context->methods->free_p(pointer);
 
 
 More Control Over aset.c Behavior
diff --git a/src/include/storage/block.h b/src/include/storage/block.h
index e2bfa11e370..182aa8d4536 100644
--- a/src/include/storage/block.h
+++ b/src/include/storage/block.h
@@ -22,7 +22,7 @@
  * contains exactly one disk block).  the blocks are numbered
  * sequentially, 0 to 0xFFFFFFFE.
  *
- * InvalidBlockNumber is the same thing as P_NEW in buf.h.
+ * InvalidBlockNumber is the same thing as P_NEW in bufmgr.h.
  *
  * the access methods, the buffer manager and the storage manager are
  * more or less the only pieces of code that should be accessing disk