diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
index 3177abcd918..67a00493606 100644
--- a/doc/src/sgml/protocol.sgml
+++ b/doc/src/sgml/protocol.sgml
@@ -1623,7 +1623,10 @@ The commands accepted in walsender mode are:
      <para>
       Requests the server to send over the timeline history file for timeline
       <replaceable class="parameter">tli</replaceable>.  Server replies with a
-      result set of a single row, containing two fields:
+      result set of a single row, containing two fields.  While the
+      fields are labeled as <type>text</type> and <type>bytea</type>,
+      they effectively return raw bytes, with no escaping or encoding
+      conversion:
      </para>
 
      <para>
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 907fdad7752..0e3b8d3694f 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -463,6 +463,10 @@ SendTimeLineHistory(TimeLineHistoryCmd *cmd)
 	pq_sendstring(&buf, "content"); /* col name */
 	pq_sendint(&buf, 0, 4);		/* table oid */
 	pq_sendint(&buf, 0, 2);		/* attnum */
+	/*
+	 * While this is labeled as BYTEAOID, it is the same output format
+	 * as TEXTOID above.
+	 */
 	pq_sendint(&buf, BYTEAOID, 4);	/* type oid */
 	pq_sendint(&buf, -1, 2);	/* typlen */
 	pq_sendint(&buf, 0, 4);		/* typmod */