diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
index 5e06c7523d..4bb1ca7e26 100644
--- a/doc/src/sgml/protocol.sgml
+++ b/doc/src/sgml/protocol.sgml
@@ -1859,7 +1859,10 @@ The commands accepted in replication 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 df27e84761..7c939897dd 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -496,6 +496,10 @@ SendTimeLineHistory(TimeLineHistoryCmd *cmd)
 	pq_sendstring(&buf, "content"); /* col name */
 	pq_sendint32(&buf, 0);		/* table oid */
 	pq_sendint16(&buf, 0);		/* attnum */
+	/*
+	 * While this is labeled as BYTEAOID, it is the same output format
+	 * as TEXTOID above.
+	 */
 	pq_sendint32(&buf, BYTEAOID);	/* type oid */
 	pq_sendint16(&buf, -1);		/* typlen */
 	pq_sendint32(&buf, 0);		/* typmod */