diff --git a/core/modules/migrate_drupal/config/migrate.migration.d6_system_cron.yml b/core/modules/migrate_drupal/config/migrate.migration.d6_system_cron.yml
index 736af9b..1e0e452 100644
--- a/core/modules/migrate_drupal/config/migrate.migration.d6_system_cron.yml
+++ b/core/modules/migrate_drupal/config/migrate.migration.d6_system_cron.yml
@@ -1,13 +1,13 @@
 id: d6_system_cron
 source:
-    plugin: drupal6_variable
-    variables:
-        - cron_threshold_warning
-        - cron_threshold_error
-        - cron_last
+  plugin: drupal6_variable
+  variables:
+    - cron_threshold_warning
+    - cron_threshold_error
+    - cron_last
 process:
-    'threshold:warning': cron_threshold_warning
-    'threshold:error': cron_threshold_error
+  'threshold:warning': cron_threshold_warning
+  'threshold:error': cron_threshold_error
 destination:
-    plugin: d8_config
-    config_name: system.cron
+  plugin: d8_config
+  config_name: system.cron
diff --git a/core/modules/migrate_drupal/config/migrate.migration.d6_system_performance.yml b/core/modules/migrate_drupal/config/migrate.migration.d6_system_performance.yml
index cde5d17..6498d9e 100644
--- a/core/modules/migrate_drupal/config/migrate.migration.d6_system_performance.yml
+++ b/core/modules/migrate_drupal/config/migrate.migration.d6_system_performance.yml
@@ -1,14 +1,14 @@
 id: d6_system_performance
 source:
-    plugin: drupal6_variable
-    variables:
-        - preprocess_css
-        - preprocess_js
-        - cache_lifetime
+  plugin: drupal6_variable
+  variables:
+    - preprocess_css
+    - preprocess_js
+    - cache_lifetime
 process:
-    'css:preprocess': preprocess_css
-    'js:preprocess': preprocess_js
-    'cache:page:max_age': cache_lifetime
+  'css:preprocess': preprocess_css
+  'js:preprocess': preprocess_js
+  'cache:page:max_age': cache_lifetime
 destination:
-    plugin: d8_config
-    config_name: system.performance
+  plugin: d8_config
+  config_name: system.performance
diff --git a/core/modules/migrate_drupal/config/migrate.migration.d6_system_rss.yml b/core/modules/migrate_drupal/config/migrate.migration.d6_system_rss.yml
index acce5e2..ca8498f 100644
--- a/core/modules/migrate_drupal/config/migrate.migration.d6_system_rss.yml
+++ b/core/modules/migrate_drupal/config/migrate.migration.d6_system_rss.yml
@@ -1,10 +1,10 @@
 id: d6_system_rss
 source:
-    plugin: drupal6_variable
-    variables:
-        - feed_default_items
+  plugin: drupal6_variable
+  variables:
+    - feed_default_items
 process:
-    'items:limit': feed_default_items
+  'items:limit': feed_default_items
 destination:
-    plugin: d8_config
-    config_name: system.rss
+  plugin: d8_config
+  config_name: system.rss
diff --git a/core/modules/migrate_drupal/config/migrate.migration.d6_system_site.yml b/core/modules/migrate_drupal/config/migrate.migration.d6_system_site.yml
index bcfb712..de88ed4 100644
--- a/core/modules/migrate_drupal/config/migrate.migration.d6_system_site.yml
+++ b/core/modules/migrate_drupal/config/migrate.migration.d6_system_site.yml
@@ -1,24 +1,24 @@
 id: d6_system_site
 source:
-    plugin: drupal6_variable
-    variables:
-        - site_name
-        - site_mail
-        - site_slogan
-        - site_frontpage
-        - site_403
-        - site_404
-        - drupal_weight_select_max
-        - admin_compact_mode
+  plugin: drupal6_variable
+  variables:
+    - site_name
+    - site_mail
+    - site_slogan
+    - site_frontpage
+    - site_403
+    - site_404
+    - drupal_weight_select_max
+    - admin_compact_mode
 process:
-    name: site_name
-    mail: site_mail
-    slogan: site_slogan
-    'page:front': site_frontpage
-    'page:403': site_403
-    'page:404': site_404
-    weight_select_max: drupal_weight_select_max
-    admin_compact_mode: admin_compact_mode
+  name: site_name
+  mail: site_mail
+  slogan: site_slogan
+  'page:front': site_frontpage
+  'page:403': site_403
+  'page:404': site_404
+  weight_select_max: drupal_weight_select_max
+  admin_compact_mode: admin_compact_mode
 destination:
-    plugin: d8_config
-    config_name: system.site
+  plugin: d8_config
+  config_name: system.site