diff --git a/core/modules/migrate/src/Plugin/migrate/process/Substr.php b/core/modules/migrate/src/Plugin/migrate/process/Substr.php
index f36da0acd597ac0f09620adefda03cb85c58b5b2..4d49a3809b70884c454c075cf24b210fdcc69cf8 100644
--- a/core/modules/migrate/src/Plugin/migrate/process/Substr.php
+++ b/core/modules/migrate/src/Plugin/migrate/process/Substr.php
@@ -33,8 +33,8 @@
  *   new_text_field:
  *     plugin: substr
  *     source: some_text_field
- *       start: 6
- *       length: 10
+ *     start: 6
+ *     length: 10
  * @endcode
  * If some_text_field was 'Marie Skłodowska Curie' then
  * $destination['new_text_field'] would be 'Skłodowska'.