diff --git a/src/tools/pgindent/README b/src/tools/pgindent/README
index a49cbe65d69..1d9aa3ca5fa 100644
--- a/src/tools/pgindent/README
+++ b/src/tools/pgindent/README
@@ -54,7 +54,7 @@ This can format all PostgreSQL *.c and *.h files, but excludes *.y, and
 	pg_ctl start
 	make installcheck-world
 
-10) Remove Perl backup files after testing
+10) Remove Perl backup files after testing (*.bak)
 
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