reverted:
--- b/core/modules/system/migration_templates/d7_system_filter.yml
+++ /dev/null
@@ -1,13 +0,0 @@
-id: d7_system_filter
-label: Drupal 7 system filter configuration
-migration_tags:
-  - Drupal 7
-source:
-  plugin: variable
-  variables:
-    - filter_allowed_protocols
-process:
-  protocols: filter_allowed_protocols
-destination:
-  plugin: config
-  config_name: system.filter
diff -u b/core/modules/system/src/Tests/Migrate/d7/MigrateSystemConfigurationTest.php b/core/modules/system/src/Tests/Migrate/d7/MigrateSystemConfigurationTest.php
--- b/core/modules/system/src/Tests/Migrate/d7/MigrateSystemConfigurationTest.php
+++ b/core/modules/system/src/Tests/Migrate/d7/MigrateSystemConfigurationTest.php
@@ -67,9 +67,6 @@
       // temporary_maximum_age is not handled by the migration.
       'temporary_maximum_age' => 21600,
     ],
-    'system.filter' => [
-      'protocols' => ['http', 'https', 'irc'],
-    ],
     'system.image.gd' => [
       'jpeg_quality' => 80,
     ],
@@ -154,21 +151,20 @@
     parent::setUp();
 
     $migrations = [
-      'd7_action_settings',
-      'd7_file_settings',
-      'd7_system_authorize',
-      'd7_system_cron',
-      'd7_system_date',
-      'd7_system_file',
-      'd7_system_filter',
-      'd7_system_image_gd',
-      'd7_system_image',
-      'd7_system_logging',
-      'd7_system_mail',
-      'd7_system_maintenance',
-      'd7_system_performance',
-      'd7_system_rss',
-      'd7_system_site',
+        'd7_action_settings',
+        'd7_file_settings',
+        'd7_system_authorize',
+        'd7_system_cron',
+        'd7_system_date',
+        'd7_system_file',
+        'd7_system_image_gd',
+        'd7_system_image',
+        'd7_system_logging',
+        'd7_system_mail',
+        'd7_system_maintenance',
+        'd7_system_performance',
+        'd7_system_rss',
+        'd7_system_site',
     ];
     $this->executeMigrations($migrations);
 
only in patch2:
unchanged:
--- a/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
+++ b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
@@ -450,6 +450,62 @@ class MigrateUpgradeForm extends ConfirmFormBase {
       'source_module' => 'system',
       'destination_module' => 'system',
     ],
+    'd7_action_settings' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_file_settings' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_authorize' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_cron' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_date' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_file' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_image_gd' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_image' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_logging' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_mail' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_maintenance' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_performance' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_rss' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
+    'd7_system_site' => [
+      'source_module' => 'system',
+      'destination_module' => 'system',
+    ],
     'menu' => [
       'source_module' => 'menu',
       'destination_module' => 'system',
only in patch2:
unchanged:
--- a/core/modules/migrate_drupal_ui/src/Tests/d7/MigrateUpgrade7Test.php
+++ b/core/modules/migrate_drupal_ui/src/Tests/d7/MigrateUpgrade7Test.php
@@ -50,7 +50,7 @@ protected function getEntityCounts() {
       'file' => 0,
       'filter_format' => 7,
       'image_style' => 6,
-      'migration' => 59,
+      'migration' => 73,
       'node' => 2,
       'node_type' => 6,
       'rdf_mapping' => 5,