only in patch2:
unchanged:
--- a/core/modules/migrate_drupal/config/install/migrate.migration.d6_comment_entity_form_display_subject.yml
+++ b/core/modules/migrate_drupal/config/install/migrate.migration.d6_comment_entity_form_display_subject.yml
@@ -1,5 +1,7 @@
 id: d6_comment_entity_form_display_subject
 label: Drupal 6 comment subject form display configuration
+migration_groups:
+  - Drupal 6
 source:
   plugin: d6_comment_variable_per_comment_type
   constants: