diff --git a/doc/src/sgml/ref/pg_basebackup.sgml b/doc/src/sgml/ref/pg_basebackup.sgml
index 57dc83b620..c4f3950e5b 100644
--- a/doc/src/sgml/ref/pg_basebackup.sgml
+++ b/doc/src/sgml/ref/pg_basebackup.sgml
@@ -306,8 +306,8 @@ PostgreSQL documentation
backup will fail and be unusable.
- The write-ahead log files will be written to
- the base.tar file.
+ When tar format mode is used, the write-ahead log files will be
+ written to the base.tar file.
@@ -326,9 +326,10 @@ PostgreSQL documentation
requires no extra write-ahead logs to be saved on the master.
- The write-ahead log files are written to a separate file
- named pg_wal.tar (if the server is a version
- earlier than 10, the file will be named pg_xlog.tar).
+ When tar format mode is used, the write-ahead log files will be
+ written to a separate file named pg_wal.tar
+ (if the server is a version earlier than 10, the file will be named
+ pg_xlog.tar).
This value is the default.