diff --git a/core/modules/migrate_drupal/src/Plugin/migrate/source/ContentEntity.php b/core/modules/migrate_drupal/src/Plugin/migrate/source/ContentEntity.php
index 42ba56d..77e4824 100644
--- a/core/modules/migrate_drupal/src/Plugin/migrate/source/ContentEntity.php
+++ b/core/modules/migrate_drupal/src/Plugin/migrate/source/ContentEntity.php
@@ -15,7 +15,15 @@
 /**
  * Source plugin to get content entities from the current version of Drupal.
  *
+ * This plugin uses the Entity API to export entity data. If the source entity
+ * type has custom field storage fields or computed fields, this class will need
+ * to be extended and the new class will need to load/calculated the values for
+ * those fields.
+ *
  * Available configuration keys:
+ * - entity_type: The entity type id of the entities being exported. This is
+ *   calculated dynamically by the deriver so it is only needed if the deriver
+ *   is not utilized i.e. a custom source plugin.
  * - bundle: (optional) String, if the entity type is bundleable, only return
  *   entities of this bundle.
  * - exclude_translations: (optional) Boolean, indicates if the entity