diff --git a/core/modules/migrate/src/Plugin/migrate/process/Migration.php b/core/modules/migrate/src/Plugin/migrate/process/Migration.php
index 18b4b71..2aa1899 100644
--- a/core/modules/migrate/src/Plugin/migrate/process/Migration.php
+++ b/core/modules/migrate/src/Plugin/migrate/process/Migration.php
@@ -25,15 +25,17 @@
  * this information is leveraged by the migration process plugin.
  *
  * Available configuration keys
- *   - migration: An array of migration ids.
- *   - source_ids:
- *   - stub_id:
+ * - migration: An array of migration ids.
+ * - source_ids: (optional) An array keyed by migration ids with values that are
+ *   a list of source properties.
+ * - stub_id: (optional) Identifies which entry in the migration array will be
+ *   used to create any stub entities.
  *
  * Examples:
  *
  * Consider a node migration, where you want to maintain authorship. If you have
- * migrated the user accounts in a migration named users, you would specify the
- * following:
+ * migrated the user accounts in a migration named "users", you would specify
+ * the following:
  *
  * @code
  * process: