diff --git a/core/config/schema/core.data_types.schema.yml b/core/config/schema/core.data_types.schema.yml
index faab88954e68..cc89fa97a6cf 100644
--- a/core/config/schema/core.data_types.schema.yml
+++ b/core/config/schema/core.data_types.schema.yml
@@ -81,6 +81,14 @@ color_hex:
 
 # Complex extended data types:
 
+# Root of a configuration object.
+config_object:
+  type: mapping
+  mapping:
+    langcode:
+      type: string
+      label: 'Language code'
+
 # Mail text with subject and body parts.
 mail:
   type: mapping
@@ -121,7 +129,7 @@ action_configuration_default:
     type: string
 
 theme_settings:
-  type: mapping
+  type: config_object
   mapping:
     favicon:
       type: mapping
@@ -183,12 +191,6 @@ theme_settings:
       sequence:
         type: theme_settings.third_party.[%key]
 
-theme_breakpoints_default:
-  type: sequence
-  sequence:
-    type: string
-    label: 'Breakpoint value'
-
 views_field_bulk_form:
   type: views_field
   label: 'Bulk operation'
@@ -262,7 +264,7 @@ config_entity:
       label: 'UUID'
     langcode:
       type: string
-      label: 'Default language'
+      label: 'Language code'
     status:
       type: boolean
       label: 'Status'
@@ -416,9 +418,6 @@ core.date_format.*:
     pattern:
       type: date_format
       label: 'PHP date format'
-    langcode:
-      type: string
-      label: 'Default language'
 
 # Generic field settings schemas.
 
diff --git a/core/config/schema/core.extension.schema.yml b/core/config/schema/core.extension.schema.yml
index f53e5e67cfe9..bdc84b9fee89 100644
--- a/core/config/schema/core.extension.schema.yml
+++ b/core/config/schema/core.extension.schema.yml
@@ -1,5 +1,5 @@
 core.extension:
-  type: mapping
+  type: config_object
   label: 'Extension settings'
   mapping:
     module:
diff --git a/core/config/schema/core.menu.schema.yml b/core/config/schema/core.menu.schema.yml
index 069ec197ba32..1a6c268e1044 100644
--- a/core/config/schema/core.menu.schema.yml
+++ b/core/config/schema/core.menu.schema.yml
@@ -1,5 +1,5 @@
 core.menu.static_menu_link_overrides:
-  type: mapping
+  type: config_object
   label: 'Static menu link overrides'
   mapping:
     definitions:
diff --git a/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php b/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
index 00bbba5b56b7..5127adc2a46c 100644
--- a/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
+++ b/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
@@ -53,7 +53,7 @@ trait SchemaCheckTrait {
     if (!$typed_config->hasConfigSchema($config_name)) {
       return FALSE;
     }
-    $definition = $typed_config->getDefinition($config_name, TRUE, TRUE);
+    $definition = $typed_config->getDefinition($config_name);
     $data_definition = $typed_config->buildDataDefinition($definition, $config_data);
     $this->schema = $typed_config->create($data_definition, $config_data);
     $errors = array();
diff --git a/core/lib/Drupal/Core/Config/StorableConfigBase.php b/core/lib/Drupal/Core/Config/StorableConfigBase.php
index 420925f20ab2..625900c28f9c 100644
--- a/core/lib/Drupal/Core/Config/StorableConfigBase.php
+++ b/core/lib/Drupal/Core/Config/StorableConfigBase.php
@@ -128,7 +128,7 @@ abstract class StorableConfigBase extends ConfigBase {
    */
   protected function getSchemaWrapper() {
     if (!isset($this->schemaWrapper)) {
-      $definition = $this->typedConfigManager->getDefinition($this->name, TRUE, TRUE);
+      $definition = $this->typedConfigManager->getDefinition($this->name);
       $data_definition = $this->typedConfigManager->buildDataDefinition($definition, $this->data);
       $this->schemaWrapper = $this->typedConfigManager->create($data_definition, $this->data);
     }
diff --git a/core/lib/Drupal/Core/Config/TypedConfigManager.php b/core/lib/Drupal/Core/Config/TypedConfigManager.php
index 6fc202b129ae..42756d63f44f 100644
--- a/core/lib/Drupal/Core/Config/TypedConfigManager.php
+++ b/core/lib/Drupal/Core/Config/TypedConfigManager.php
@@ -72,7 +72,7 @@ class TypedConfigManager extends TypedDataManager implements TypedConfigManagerI
    */
   public function get($name) {
     $data = $this->configStorage->read($name);
-    $type_definition = $this->getDefinition($name, TRUE, TRUE);
+    $type_definition = $this->getDefinition($name);
     $data_definition = $this->buildDataDefinition($type_definition, $data);
     return $this->create($data_definition, $data);
   }
diff --git a/core/lib/Drupal/Core/Config/TypedConfigManagerInterface.php b/core/lib/Drupal/Core/Config/TypedConfigManagerInterface.php
index 402cb8222e46..e9e562e92eb6 100644
--- a/core/lib/Drupal/Core/Config/TypedConfigManagerInterface.php
+++ b/core/lib/Drupal/Core/Config/TypedConfigManagerInterface.php
@@ -111,8 +111,8 @@ Interface TypedConfigManagerInterface extends PluginManagerInterface, CachedDisc
    *   Ignored with TypedConfigManagerInterface. Kept for compatibility with
    *   DiscoveryInterface.
    * @param bool $is_config_name
-   *   Set to TRUE if $plugin_id is a configuration name (as opposed to an
-   *   internal configuration schema type).
+   *   (deprecated) Set to TRUE if $plugin_id is a configuration name (as
+   *   opposed to an internal configuration schema type).
    *
    * @return array
    *   A plugin definition array. If the given plugin id does not have typed
diff --git a/core/modules/action/config/schema/action.schema.yml b/core/modules/action/config/schema/action.schema.yml
index cd4e02c8043f..421e05fd1829 100644
--- a/core/modules/action/config/schema/action.schema.yml
+++ b/core/modules/action/config/schema/action.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Action module.
 
 action.settings:
-  type: mapping
+  type: config_object
   label: 'Action settings'
   mapping:
     recursion_limit:
diff --git a/core/modules/aggregator/config/schema/aggregator.schema.yml b/core/modules/aggregator/config/schema/aggregator.schema.yml
index 97b3d3fd9d75..85710b85c176 100644
--- a/core/modules/aggregator/config/schema/aggregator.schema.yml
+++ b/core/modules/aggregator/config/schema/aggregator.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the aggregator module.
 
 aggregator.settings:
-  type: mapping
+  type: config_object
   label: 'Aggregator settings'
   mapping:
     fetcher:
diff --git a/core/modules/aggregator/tests/modules/aggregator_test/config/schema/aggregator_test.schema.yml b/core/modules/aggregator/tests/modules/aggregator_test/config/schema/aggregator_test.schema.yml
index 63347daf5419..61d34413e522 100644
--- a/core/modules/aggregator/tests/modules/aggregator_test/config/schema/aggregator_test.schema.yml
+++ b/core/modules/aggregator/tests/modules/aggregator_test/config/schema/aggregator_test.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Aggregator Test module.
 
 aggregator_test.settings:
-  type: mapping
+  type: config_object
   label: 'Aggregator test settings'
   mapping:
     items:
diff --git a/core/modules/book/config/schema/book.schema.yml b/core/modules/book/config/schema/book.schema.yml
index c9fb1bf5bd6f..97d2f933d7ce 100644
--- a/core/modules/book/config/schema/book.schema.yml
+++ b/core/modules/book/config/schema/book.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the book module.
 
 book.settings:
-  type: mapping
+  type: config_object
   label: 'Book settings'
   mapping:
     allowed_types:
diff --git a/core/modules/color/config/schema/color.schema.yml b/core/modules/color/config/schema/color.schema.yml
index 008148cc1f9e..07ae1cccebf3 100644
--- a/core/modules/color/config/schema/color.schema.yml
+++ b/core/modules/color/config/schema/color.schema.yml
@@ -1,5 +1,5 @@
 color.theme.*:
-  type: mapping
+  type: config_object
   label: 'Color theme settings'
   mapping:
     palette:
diff --git a/core/modules/config/src/Tests/ConfigSchemaTest.php b/core/modules/config/src/Tests/ConfigSchemaTest.php
index cf945d98a8cf..4082dfa96c4a 100644
--- a/core/modules/config/src/Tests/ConfigSchemaTest.php
+++ b/core/modules/config/src/Tests/ConfigSchemaTest.php
@@ -61,6 +61,8 @@ class ConfigSchemaTest extends KernelTestBase {
     $expected = array();
     $expected['label'] = 'Schema test data';
     $expected['class'] = '\Drupal\Core\Config\Schema\Mapping';
+    $expected['mapping']['langcode']['type'] = 'string';
+    $expected['mapping']['langcode']['label'] = 'Language code';
     $expected['mapping']['testitem'] = array('label' => 'Test item');
     $expected['mapping']['testlist'] = array('label' => 'Test list');
     $expected['type'] = 'config_schema_test.someschema';
@@ -101,7 +103,7 @@ class ConfigSchemaTest extends KernelTestBase {
       'type' => 'text',
     );
     $expected['mapping']['langcode'] = array(
-      'label' => 'Default language',
+      'label' => 'Language code',
       'type' => 'string',
     );
     $expected['type'] = 'system.maintenance';
@@ -114,6 +116,10 @@ class ConfigSchemaTest extends KernelTestBase {
     $expected['label'] = 'Ignore test';
     $expected['class'] = '\Drupal\Core\Config\Schema\Mapping';
     $expected['definition_class'] = '\Drupal\Core\TypedData\MapDataDefinition';
+    $expected['mapping']['langcode'] = array(
+      'type' => 'string',
+      'label' => 'Language code',
+    );
     $expected['mapping']['label'] = array(
       'label' =>  'Label',
       'type' => 'label',
@@ -156,7 +162,7 @@ class ConfigSchemaTest extends KernelTestBase {
     $expected['mapping']['uuid']['type'] = 'string';
     $expected['mapping']['uuid']['label'] = 'UUID';
     $expected['mapping']['langcode']['type'] = 'string';
-    $expected['mapping']['langcode']['label'] = 'Default language';
+    $expected['mapping']['langcode']['label'] = 'Language code';
     $expected['mapping']['status']['type'] = 'boolean';
     $expected['mapping']['status']['label'] = 'Status';
     $expected['mapping']['dependencies']['type'] = 'config_dependencies';
@@ -222,6 +228,8 @@ class ConfigSchemaTest extends KernelTestBase {
     $expected = array();
     $expected['label'] = 'Schema multiple filesytem marker test';
     $expected['class'] = '\Drupal\Core\Config\Schema\Mapping';
+    $expected['mapping']['langcode']['type'] = 'string';
+    $expected['mapping']['langcode']['label'] = 'Language code';
     $expected['mapping']['testid']['type'] = 'string';
     $expected['mapping']['testid']['label'] = 'ID';
     $expected['mapping']['testdescription']['type'] = 'text';
@@ -396,6 +404,8 @@ class ConfigSchemaTest extends KernelTestBase {
     $expected['label'] = 'Schema wildcard fallback test';
     $expected['class'] = '\Drupal\Core\Config\Schema\Mapping';
     $expected['definition_class'] = '\Drupal\Core\TypedData\MapDataDefinition';
+    $expected['mapping']['langcode']['type'] = 'string';
+    $expected['mapping']['langcode']['label'] = 'Language code';
     $expected['mapping']['testid']['type'] = 'string';
     $expected['mapping']['testid']['label'] = 'ID';
     $expected['mapping']['testdescription']['type'] = 'text';
diff --git a/core/modules/config/tests/config_collection_install_test/config/schema/config_collection_install_test.schema.yml b/core/modules/config/tests/config_collection_install_test/config/schema/config_collection_install_test.schema.yml
index 6e93f9717a5d..e038e9fc24af 100644
--- a/core/modules/config/tests/config_collection_install_test/config/schema/config_collection_install_test.schema.yml
+++ b/core/modules/config/tests/config_collection_install_test/config/schema/config_collection_install_test.schema.yml
@@ -1,5 +1,5 @@
 config_collection_install_test.test:
-  type: mapping
+  type: config_object
   label: 'Collection test'
   mapping:
     collection:
diff --git a/core/modules/config/tests/config_events_test/config/schema/config_events_test.schema.yml b/core/modules/config/tests/config_events_test/config/schema/config_events_test.schema.yml
index e3005b1ce12b..2153cc24fa34 100644
--- a/core/modules/config/tests/config_events_test/config/schema/config_events_test.schema.yml
+++ b/core/modules/config/tests/config_events_test/config/schema/config_events_test.schema.yml
@@ -1,5 +1,5 @@
 config_events_test.test:
-  type: mapping
+  type: config_object
   label: 'Configuration events test'
   mapping:
     key:
diff --git a/core/modules/config/tests/config_integration_test/config/schema/config_integration_test.schema.yml b/core/modules/config/tests/config_integration_test/config/schema/config_integration_test.schema.yml
index 5010f01ffd93..337a721554d6 100644
--- a/core/modules/config/tests/config_integration_test/config/schema/config_integration_test.schema.yml
+++ b/core/modules/config/tests/config_integration_test/config/schema/config_integration_test.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Configuration Integration Test module.
 
 config_integration_test.settings:
-  type: mapping
+  type: config_object
   label: 'Configuration integration test settings'
   mapping:
     foo:
diff --git a/core/modules/config/tests/config_schema_test/config/schema/config_schema_test.schema.yml b/core/modules/config/tests/config_schema_test/config/schema/config_schema_test.schema.yml
index 6b4f62d25a45..7c18496baf5d 100644
--- a/core/modules/config/tests/config_schema_test/config/schema/config_schema_test.schema.yml
+++ b/core/modules/config/tests/config_schema_test/config/schema/config_schema_test.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Configuration Schema Test module.
 
 config_schema_test.someschema:
-  type: mapping
+  type: config_object
   label: 'Schema test data'
   mapping:
     testitem:
@@ -11,7 +11,7 @@ config_schema_test.someschema:
 
 config_schema_test.someschema.with_parents:
   label: 'Schema test data with parenting'
-  type: mapping
+  type: config_object
   mapping:
     one_level:
       label: 'Parenting one level up'
@@ -64,7 +64,7 @@ config_schema_test.someschema.with_parents.key_3:
   type: string
 
 config_schema_test.someschema.somemodule.*.*:
-  type: mapping
+  type: config_object
   label: 'Schema multiple filesytem marker test'
   mapping:
     testid:
@@ -75,7 +75,7 @@ config_schema_test.someschema.somemodule.*.*:
       label: 'Description'
 
 config_schema_test.wildcard_fallback.*:
-  type: mapping
+  type: config_object
   label: 'Schema wildcard fallback test'
   mapping:
     testid:
@@ -86,7 +86,7 @@ config_schema_test.wildcard_fallback.*:
       label: 'Description'
 
 config_schema_test.schema_data_types:
-  type: mapping
+  type: config_object
   label: 'Config test schema'
   mapping:
     config_schema_test_integer:
@@ -127,7 +127,7 @@ config_schema_test.schema_data_types:
 
 config_schema_test.schema_in_install:
   label: 'Schema test data with parenting'
-  type: mapping
+  type: config_object
   mapping:
     integer:
       type: integer
@@ -138,7 +138,7 @@ config_schema_test_integer:
   label: 'Config test integer'
 
 config_schema_test.ignore:
-  type: mapping
+  type: config_object
   label: 'Ignore test'
   mapping:
     label:
@@ -155,7 +155,7 @@ config_schema_test.ignore:
       label: 'Weight'
 
 config_schema_test.plugin_types:
-  type: mapping
+  type: config_object
   mapping:
     tests:
       type: sequence
diff --git a/core/modules/config/tests/config_test/config/schema/config_test.schema.yml b/core/modules/config/tests/config_test/config/schema/config_test.schema.yml
index e964db3152e7..6cad91b25f2d 100644
--- a/core/modules/config/tests/config_test/config/schema/config_test.schema.yml
+++ b/core/modules/config/tests/config_test/config/schema/config_test.schema.yml
@@ -56,7 +56,7 @@ config_test.query.*:
       label: 'number'
 
 config_test.types:
-  type: mapping
+  type: config_object
   label: 'Configuration type'
   mapping:
     array:
@@ -94,7 +94,7 @@ config_test.types:
       label: 'String integer'
 
 config_test.no_status.default:
-  type: mapping
+  type: config_object
   label: 'Configuration no status default'
   mapping:
     id:
@@ -105,7 +105,7 @@ config_test.no_status.default:
       label: 'Label'
 
 config_test.system:
-  type: mapping
+  type: config_object
   label: 'Configuration system'
   mapping:
     foo:
@@ -119,7 +119,7 @@ config_test.system:
       label: '404'
 
 config_test.new:
-  type: mapping
+  type: config_object
   label: 'Configuration test'
   mapping:
      key:
@@ -136,7 +136,7 @@ config_test.old:
   type: config_test.new
 
 config_test.foo:
-  type: mapping
+  type: config_object
   label: 'Configuration test'
   mapping:
      value:
diff --git a/core/modules/config_translation/tests/modules/config_translation_test/config/schema/config_translation_test.schema.yml b/core/modules/config_translation/tests/modules/config_translation_test/config/schema/config_translation_test.schema.yml
index a5ff2e6c89b6..63b84751d7e7 100644
--- a/core/modules/config_translation/tests/modules/config_translation_test/config/schema/config_translation_test.schema.yml
+++ b/core/modules/config_translation/tests/modules/config_translation_test/config/schema/config_translation_test.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Configuration translation test module.
 
 config_translation_test.content:
-  type: mapping
+  type: config_object
   label: 'Content'
   mapping:
     id:
@@ -10,9 +10,6 @@ config_translation_test.content:
     label:
       type: label
       label: 'Label'
-    langcode:
-      type: string
-      label: 'Default language'
     content:
       type: text_format
       label: 'Content'
diff --git a/core/modules/contact/config/schema/contact.schema.yml b/core/modules/contact/config/schema/contact.schema.yml
index 080a9c89c1f6..5a62e9da32e4 100644
--- a/core/modules/contact/config/schema/contact.schema.yml
+++ b/core/modules/contact/config/schema/contact.schema.yml
@@ -24,7 +24,7 @@ contact.form.*:
       label: 'Weight'
 
 contact.settings:
-  type: mapping
+  type: config_object
   label: 'Contact settings'
   mapping:
     default_form:
diff --git a/core/modules/dblog/config/schema/dblog.schema.yml b/core/modules/dblog/config/schema/dblog.schema.yml
index dfb6422cb32a..d7196da6da47 100644
--- a/core/modules/dblog/config/schema/dblog.schema.yml
+++ b/core/modules/dblog/config/schema/dblog.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the dblog module.
 
 dblog.settings:
-  type: mapping
+  type: config_object
   label: 'Database logging settings'
   mapping:
     row_limit:
diff --git a/core/modules/field/config/schema/field.schema.yml b/core/modules/field/config/schema/field.schema.yml
index 9ea9b2edaecf..55760a74f772 100644
--- a/core/modules/field/config/schema/field.schema.yml
+++ b/core/modules/field/config/schema/field.schema.yml
@@ -1,7 +1,7 @@
 # Schema for configuration files of the Field module.
 
 field.settings:
-  type: mapping
+  type: config_object
   label: 'Field settings'
   mapping:
     purge_batch_size:
diff --git a/core/modules/field_ui/config/schema/field_ui.schema.yml b/core/modules/field_ui/config/schema/field_ui.schema.yml
index fe7e95c2e052..f5421c38e179 100644
--- a/core/modules/field_ui/config/schema/field_ui.schema.yml
+++ b/core/modules/field_ui/config/schema/field_ui.schema.yml
@@ -1,7 +1,7 @@
 # Schema for configuration files of the Field UI module.
 
 field_ui.settings:
-  type: mapping
+  type: config_object
   label: 'Field UI settings'
   mapping:
     field_prefix:
diff --git a/core/modules/file/config/schema/file.schema.yml b/core/modules/file/config/schema/file.schema.yml
index bbf4048c1616..e5892e57d417 100644
--- a/core/modules/file/config/schema/file.schema.yml
+++ b/core/modules/file/config/schema/file.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the File module.
 
 file.settings:
-  type: mapping
+  type: config_object
   label: 'File settings'
   mapping:
     description:
diff --git a/core/modules/filter/config/schema/filter.schema.yml b/core/modules/filter/config/schema/filter.schema.yml
index ac956f7c39cf..b45a4755958c 100644
--- a/core/modules/filter/config/schema/filter.schema.yml
+++ b/core/modules/filter/config/schema/filter.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Filter module.
 
 filter.settings:
-  type: mapping
+  type: config_object
   label: 'Filter settings'
   mapping:
     fallback_format:
@@ -35,9 +35,6 @@ filter.format.*:
       label: 'Enabled filters'
       sequence:
         type: filter
-    langcode:
-      type: string
-      label: 'Default language'
     dependencies:
       type: config_dependencies
       label: 'Dependencies'
diff --git a/core/modules/forum/config/schema/forum.schema.yml b/core/modules/forum/config/schema/forum.schema.yml
index 2e01710cba4e..dbe44fc91fe6 100644
--- a/core/modules/forum/config/schema/forum.schema.yml
+++ b/core/modules/forum/config/schema/forum.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Forum module.
 
 forum.settings:
-  type: mapping
+  type: config_object
   label: 'Forum settings'
   mapping:
     block:
diff --git a/core/modules/image/config/schema/image.schema.yml b/core/modules/image/config/schema/image.schema.yml
index 41dbb98262d9..4949fa3ef4a8 100644
--- a/core/modules/image/config/schema/image.schema.yml
+++ b/core/modules/image/config/schema/image.schema.yml
@@ -70,7 +70,7 @@ image.effect.image_scale_and_crop:
   label: 'Image scale and crop'
 
 image.settings:
-  type: mapping
+  type: config_object
   mapping:
     preview_image:
       type: string
diff --git a/core/modules/language/config/install/language.mappings.yml b/core/modules/language/config/install/language.mappings.yml
index f7fc321557ab..5c6419364292 100644
--- a/core/modules/language/config/install/language.mappings.yml
+++ b/core/modules/language/config/install/language.mappings.yml
@@ -1,12 +1,13 @@
 # Browsers use different language codes to refer to the same languages,
 # these defaults handles the most common cases.
-no: 'nb' # Norwegian
-pt: 'pt-pt' # Portuguese
-zh: 'zh-hans' # Default Chinese to simplified script
-zh-tw: 'zh-hant' # Taiwan Chinese in traditional script
-zh-hk: 'zh-hant' # Hong Kong Chinese in traditional script
-zh-mo: 'zh-hant' # Macao Chinese in traditional script
-zh-cht: 'zh-hant' # traditional Chinese
-zh-cn: 'zh-hans' # PRC Mainland Chinese in simplified script
-zh-sg: 'zh-hans' # Singapore Chinese in simplified script
-zh-chs: 'zh-hans' # simplified Chinese
+map:
+  no: 'nb' # Norwegian
+  pt: 'pt-pt' # Portuguese
+  zh: 'zh-hans' # Default Chinese to simplified script
+  zh-tw: 'zh-hant' # Taiwan Chinese in traditional script
+  zh-hk: 'zh-hant' # Hong Kong Chinese in traditional script
+  zh-mo: 'zh-hant' # Macao Chinese in traditional script
+  zh-cht: 'zh-hant' # traditional Chinese
+  zh-cn: 'zh-hans' # PRC Mainland Chinese in simplified script
+  zh-sg: 'zh-hans' # Singapore Chinese in simplified script
+  zh-chs: 'zh-hans' # simplified Chinese
diff --git a/core/modules/language/config/schema/language.schema.yml b/core/modules/language/config/schema/language.schema.yml
index 6c082e110760..5e3f55b5f756 100644
--- a/core/modules/language/config/schema/language.schema.yml
+++ b/core/modules/language/config/schema/language.schema.yml
@@ -18,7 +18,7 @@ language_type_negotiation:
         label: Weight
 
 language.types:
-  type: mapping
+  type: config_object
   label: 'Language types'
   mapping:
     all:
@@ -41,7 +41,7 @@ language.types:
         label: 'Language negotiation per type setting'
 
 language.negotiation:
-  type: mapping
+  type: config_object
   label: 'Language detection methods'
   mapping:
     session:
@@ -75,11 +75,14 @@ language.negotiation:
       label: 'Selected language'
 
 language.mappings:
-  type: sequence
+  type: config_object
   label: 'Language mapping'
-  sequence:
-    type: string
-    label: 'Language'
+  mapping:
+    map:
+      type: sequence
+      sequence:
+        type: string
+        label: 'Language'
 
 language.entity.*:
   type: config_entity
diff --git a/core/modules/language/language.module b/core/modules/language/language.module
index ae8c2e2f5fd4..4e7f017f9d56 100644
--- a/core/modules/language/language.module
+++ b/core/modules/language/language.module
@@ -448,7 +448,7 @@ function language_get_browser_drupal_langcode_mappings() {
   if ($config->isNew()) {
     return array();
   }
-  return $config->get();
+  return $config->get('map');
 }
 
 /**
diff --git a/core/modules/language/src/Form/NegotiationBrowserDeleteForm.php b/core/modules/language/src/Form/NegotiationBrowserDeleteForm.php
index 1dc1447522de..73e0246a9419 100644
--- a/core/modules/language/src/Form/NegotiationBrowserDeleteForm.php
+++ b/core/modules/language/src/Form/NegotiationBrowserDeleteForm.php
@@ -71,7 +71,7 @@ class NegotiationBrowserDeleteForm extends ConfirmFormBase {
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $this->config('language.mappings')
-      ->clear($this->browserLangcode)
+      ->clear('map.' . $this->browserLangcode)
       ->save();
 
     $args = array(
diff --git a/core/modules/language/src/Form/NegotiationBrowserForm.php b/core/modules/language/src/Form/NegotiationBrowserForm.php
index 14ebb625985f..bf0ce4eb0028 100644
--- a/core/modules/language/src/Form/NegotiationBrowserForm.php
+++ b/core/modules/language/src/Form/NegotiationBrowserForm.php
@@ -180,7 +180,7 @@ class NegotiationBrowserForm extends ConfigFormBase {
     $mappings = $form_state->get('mappings');
     if (!empty($mappings)) {
       $config = $this->config('language.mappings');
-      $config->setData($mappings);
+      $config->setData(['map' => $mappings]);
       $config->save();
     }
 
@@ -198,7 +198,7 @@ class NegotiationBrowserForm extends ConfigFormBase {
     if ($config->isNew()) {
       return array();
     }
-    return $config->get();
+    return $config->get('map');
   }
 }
 
diff --git a/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationBrowser.php b/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationBrowser.php
index e9fc38e00e8e..9acd295bf169 100644
--- a/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationBrowser.php
+++ b/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationBrowser.php
@@ -39,7 +39,7 @@ class LanguageNegotiationBrowser extends LanguageNegotiationMethodBase {
     if ($this->languageManager && $request && $request->server->get('HTTP_ACCEPT_LANGUAGE')) {
       $http_accept_language = $request->server->get('HTTP_ACCEPT_LANGUAGE');
       $langcodes = array_keys($this->languageManager->getLanguages());
-      $mappings = $this->config->get('language.mappings')->get();
+      $mappings = $this->config->get('language.mappings')->get('map');
       $langcode = UserAgent::getBestMatchingLangcode($http_accept_language, $langcodes, $mappings);
     }
 
diff --git a/core/modules/locale/config/schema/locale.schema.yml b/core/modules/locale/config/schema/locale.schema.yml
index 72b89e1547b9..7321f60113f0 100644
--- a/core/modules/locale/config/schema/locale.schema.yml
+++ b/core/modules/locale/config/schema/locale.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Locale module.
 
 locale.settings:
-  type: mapping
+  type: config_object
   label: 'Translate interface settings'
   mapping:
     cache_strings:
diff --git a/core/modules/locale/src/LocaleConfigManager.php b/core/modules/locale/src/LocaleConfigManager.php
index 17d1e8f5e4fa..d10cf188a3bf 100644
--- a/core/modules/locale/src/LocaleConfigManager.php
+++ b/core/modules/locale/src/LocaleConfigManager.php
@@ -134,7 +134,7 @@ class LocaleConfigManager {
     if ($this->isSupported($name)) {
       // Create typed configuration wrapper based on install storage data.
       $data = $this->installStorageRead($name);
-      $type_definition = $this->typedConfigManager->getDefinition($name, TRUE, TRUE);
+      $type_definition = $this->typedConfigManager->getDefinition($name);
       $data_definition = $this->typedConfigManager->buildDataDefinition($type_definition, $data);
       $typed_config = $this->typedConfigManager->create($data_definition, $data);
       if ($typed_config instanceof TraversableTypedDataInterface) {
diff --git a/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml b/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml
index daf3391e3ac7..f6cf7b900f89 100644
--- a/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml
+++ b/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Locale Test module.
 
 locale_test.no_translation:
-  type: mapping
+  type: config_object
   label: 'No traslation settings'
   mapping:
     test:
@@ -9,11 +9,9 @@ locale_test.no_translation:
       label: 'Test'
       # See \Drupal\locale\Tests\LocaleConfigSubscriberTest
       translatable: true
-    langcode:
-      type: string
 
 locale_test.translation:
-  type: mapping
+  type: config_object
   label: 'translation settings'
   mapping:
     test:
@@ -21,5 +19,3 @@ locale_test.translation:
       label: 'Test'
       # See \Drupal\locale\Tests\LocaleConfigSubscriberTest
       translatable: true
-    langcode:
-      type: string
diff --git a/core/modules/migrate_drupal/config/schema/migrate_drupal.source.schema.yml b/core/modules/migrate_drupal/config/schema/migrate_drupal.source.schema.yml
index f48c43e395bd..56ba96010606 100644
--- a/core/modules/migrate_drupal/config/schema/migrate_drupal.source.schema.yml
+++ b/core/modules/migrate_drupal/config/schema/migrate_drupal.source.schema.yml
@@ -331,7 +331,7 @@ migrate_entity_constant:
       label: 'Parent'
     langcode:
       type: string
-      label: 'Type'
+      label: 'Language code'
     third_party_settings:
       type: sequence
       label: 'Settings'
diff --git a/core/modules/node/config/schema/node.schema.yml b/core/modules/node/config/schema/node.schema.yml
index 3ec6c8e0ee14..dbc8ac9d9dea 100644
--- a/core/modules/node/config/schema/node.schema.yml
+++ b/core/modules/node/config/schema/node.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the node module.
 
 node.settings:
-  type: mapping
+  type: config_object
   label: 'Node settings'
   mapping:
     use_admin_theme:
diff --git a/core/modules/rest/config/schema/rest.schema.yml b/core/modules/rest/config/schema/rest.schema.yml
index 21952ae1d839..8421d13e896d 100644
--- a/core/modules/rest/config/schema/rest.schema.yml
+++ b/core/modules/rest/config/schema/rest.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the REST module.
 
 rest.settings:
-  type: mapping
+  type: config_object
   label: 'REST settings'
   mapping:
     resources:
diff --git a/core/modules/search/config/schema/search.schema.yml b/core/modules/search/config/schema/search.schema.yml
index 450c60c2d861..2ed4c09ba9a8 100644
--- a/core/modules/search/config/schema/search.schema.yml
+++ b/core/modules/search/config/schema/search.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the search module.
 
 search.settings:
-  type: mapping
+  type: config_object
   label: 'Search settings'
   mapping:
     and_or_limit:
diff --git a/core/modules/simpletest/config/schema/simpletest.schema.yml b/core/modules/simpletest/config/schema/simpletest.schema.yml
index 5423adc08009..827ef560126b 100644
--- a/core/modules/simpletest/config/schema/simpletest.schema.yml
+++ b/core/modules/simpletest/config/schema/simpletest.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Simpletest module.
 
 simpletest.settings:
-  type: mapping
+  type: config_object
   label: 'Testing'
   mapping:
     clear_results:
diff --git a/core/modules/statistics/config/schema/statistics.schema.yml b/core/modules/statistics/config/schema/statistics.schema.yml
index ff64363e80c8..81ed4381576b 100644
--- a/core/modules/statistics/config/schema/statistics.schema.yml
+++ b/core/modules/statistics/config/schema/statistics.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the statistics module.
 
 statistics.settings:
-  type: mapping
+  type: config_object
   label: 'Statistics settings'
   mapping:
     access_log:
diff --git a/core/modules/syslog/config/schema/syslog.schema.yml b/core/modules/syslog/config/schema/syslog.schema.yml
index f2e7ca7f0059..5d2707a5a151 100644
--- a/core/modules/syslog/config/schema/syslog.schema.yml
+++ b/core/modules/syslog/config/schema/syslog.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the syslog module.
 
 syslog.settings:
-  type: mapping
+  type: config_object
   label: 'Syslog settings'
   mapping:
     identity:
diff --git a/core/modules/system/config/schema/system.schema.yml b/core/modules/system/config/schema/system.schema.yml
index ba8fa1598b34..3ba947eb84ed 100644
--- a/core/modules/system/config/schema/system.schema.yml
+++ b/core/modules/system/config/schema/system.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the System module.
 
 system.site:
-  type: mapping
+  type: config_object
   label: 'Site information'
   mapping:
     uuid:
@@ -35,9 +35,6 @@ system.site:
     weight_select_max:
       type: integer
       label: 'Weight element maximum value'
-    langcode:
-      type: string
-      label: 'Language code'
     default_langcode:
       type: string
       label: 'Site default language code'
@@ -46,18 +43,15 @@ system.site:
       label: 'Notification email address'
 
 system.maintenance:
-  type: mapping
+  type: config_object
   label: 'Maintenance mode'
   mapping:
     message:
       type: text
       label: 'Message to display when in maintenance mode'
-    langcode:
-      type: string
-      label: 'Default language'
 
 system.authorize:
-  type: mapping
+  type: config_object
   label: 'Authorize settings'
   mapping:
     filetransfer_default:
@@ -65,7 +59,7 @@ system.authorize:
       label: 'Default file transfer protocol'
 
 system.cron:
-  type: mapping
+  type: config_object
   label: 'Cron settings'
   mapping:
     threshold:
@@ -83,7 +77,7 @@ system.cron:
           label: 'Requirements error period'
 
 system.date:
-  type: mapping
+  type: config_object
   label: 'Date settings'
   mapping:
     first_day:
@@ -96,9 +90,6 @@ system.date:
         default:
           type: string
           label: 'Default country'
-    langcode:
-      type: string
-      label: 'Default language'
     timezone:
       type: mapping
       label: 'Time zone settings'
@@ -121,7 +112,7 @@ system.date:
               label: 'Remind users at login if their time zone is not set'
 
 system.diff:
-  type: mapping
+  type: config_object
   label: 'Diff settings'
   mapping:
     context:
@@ -136,7 +127,7 @@ system.diff:
           label: 'Number of trailing lines in a diff'
 
 system.filter:
-  type: mapping
+  type: config_object
   label: 'Filter settings'
   mapping:
     protocols:
@@ -147,7 +138,7 @@ system.filter:
         label: 'Protocol'
 
 system.logging:
-  type: mapping
+  type: config_object
   label: 'Logging settings'
   mapping:
     error_level:
@@ -155,7 +146,7 @@ system.logging:
       label: 'Error messages to display'
 
 system.performance:
-  type: mapping
+  type: config_object
   label: 'Performance settings'
   mapping:
     cache:
@@ -220,7 +211,7 @@ system.performance:
       label: 'Stale file threshold'
 
 system.rss:
-  type: mapping
+  type: config_object
   label: 'Feed settings'
   mapping:
     channel:
@@ -240,12 +231,9 @@ system.rss:
         view_mode:
           type: string
           label: 'Feed content'
-    langcode:
-      type: string
-      label: 'Default language'
 
 system.theme:
-  type: mapping
+  type: config_object
   label: 'Theme settings'
   mapping:
     admin:
@@ -292,7 +280,7 @@ system.action.*:
       type: action.configuration.[%parent.plugin]
 
 system.file:
-  type: mapping
+  type: config_object
   label: 'File system'
   mapping:
     allow_insecure_uploads:
@@ -313,7 +301,7 @@ system.file:
       label: 'Maximum age for temporary files'
 
 system.image:
-  type: mapping
+  type: config_object
   label: 'Image settings'
   mapping:
     toolkit:
@@ -321,7 +309,7 @@ system.image:
       label: 'Toolkit'
 
 system.image.gd:
-  type: mapping
+  type: config_object
   label: 'Image settings'
   mapping:
     jpeg_quality:
@@ -329,7 +317,7 @@ system.image.gd:
       label: 'JPEG quality'
 
 system.mail:
-  type: mapping
+  type: config_object
   label: 'Mail system'
   mapping:
     interface:
diff --git a/core/modules/system/tests/modules/form_test/config/schema/form_test.schema.yml b/core/modules/system/tests/modules/form_test/config/schema/form_test.schema.yml
index 3e38933008fd..9af17cdd860c 100644
--- a/core/modules/system/tests/modules/form_test/config/schema/form_test.schema.yml
+++ b/core/modules/system/tests/modules/form_test/config/schema/form_test.schema.yml
@@ -1,5 +1,5 @@
 form_test.object:
-  type: mapping
+  type: config_object
   label: 'Test form'
   mapping:
     bananas:
diff --git a/core/modules/system/tests/modules/update_script_test/config/schema/update_script_test.schema.yml b/core/modules/system/tests/modules/update_script_test/config/schema/update_script_test.schema.yml
index 6efa59433ec8..cc4031d29203 100644
--- a/core/modules/system/tests/modules/update_script_test/config/schema/update_script_test.schema.yml
+++ b/core/modules/system/tests/modules/update_script_test/config/schema/update_script_test.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Update Script Test module.
 
 update_script_test.settings:
-  type: mapping
+  type: config_object
   label: ''
   mapping:
     requirement_type:
diff --git a/core/modules/taxonomy/config/schema/taxonomy.schema.yml b/core/modules/taxonomy/config/schema/taxonomy.schema.yml
index ef56111625be..efa08e154e69 100644
--- a/core/modules/taxonomy/config/schema/taxonomy.schema.yml
+++ b/core/modules/taxonomy/config/schema/taxonomy.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Taxonomy module.
 
 taxonomy.settings:
-  type: mapping
+  type: config_object
   label: 'Taxonomy settings'
   mapping:
     maintain_index_table:
diff --git a/core/modules/text/config/schema/text.schema.yml b/core/modules/text/config/schema/text.schema.yml
index 03d9969e3364..dfc92cd2ba14 100644
--- a/core/modules/text/config/schema/text.schema.yml
+++ b/core/modules/text/config/schema/text.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the text module.
 
 text.settings:
-  type: mapping
+  type: config_object
   label: 'Text settings'
   mapping:
     default_summary_length:
diff --git a/core/modules/tracker/config/schema/tracker.schema.yml b/core/modules/tracker/config/schema/tracker.schema.yml
index ccfe05312d15..ace7ec7183ea 100644
--- a/core/modules/tracker/config/schema/tracker.schema.yml
+++ b/core/modules/tracker/config/schema/tracker.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the tracker module.
 
 tracker.settings:
-  type: mapping
+  type: config_object
   label: 'Tracker settings'
   mapping:
     cron_index_limit:
diff --git a/core/modules/update/config/schema/update.schema.yml b/core/modules/update/config/schema/update.schema.yml
index ee1924a833bf..b827c564d3df 100644
--- a/core/modules/update/config/schema/update.schema.yml
+++ b/core/modules/update/config/schema/update.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Update module.
 
 update.settings:
-  type: mapping
+  type: config_object
   label: 'Update settings'
   mapping:
     check:
diff --git a/core/modules/update/tests/modules/update_test/config/schema/update_test.schema.yml b/core/modules/update/tests/modules/update_test/config/schema/update_test.schema.yml
index 69a84b743e25..c14e7985eb01 100644
--- a/core/modules/update/tests/modules/update_test/config/schema/update_test.schema.yml
+++ b/core/modules/update/tests/modules/update_test/config/schema/update_test.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Update Test module.
 
 update_test.settings:
-  type: mapping
+  type: config_object
   label: 'Update test settings'
   mapping:
     system_info:
diff --git a/core/modules/user/config/schema/user.schema.yml b/core/modules/user/config/schema/user.schema.yml
index 09e5989e9714..9d853c17fd4f 100644
--- a/core/modules/user/config/schema/user.schema.yml
+++ b/core/modules/user/config/schema/user.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the User module.
 
 user.settings:
-  type: mapping
+  type: config_object
   label: 'User settings'
   mapping:
     anonymous:
@@ -50,12 +50,9 @@ user.settings:
     password_strength:
       type: boolean
       label: 'Enable password strength indicator'
-    langcode:
-      type: string
-      label: 'Default language'
 
 user.mail:
- type: mapping
+ type: config_object
  label: 'Email settings'
  mapping:
   cancel_confirm:
@@ -85,12 +82,9 @@ user.mail:
   status_canceled:
     type: mail
     label: 'Account cancelled'
-  langcode:
-    type: string
-    label: 'Default language'
 
 user.flood:
-  type: mapping
+  type: config_object
   label: 'User flood settings'
   mapping:
     uid_only:
diff --git a/core/modules/views/config/schema/views.schema.yml b/core/modules/views/config/schema/views.schema.yml
index e3293a17ae22..7ea599d32ec4 100644
--- a/core/modules/views/config/schema/views.schema.yml
+++ b/core/modules/views/config/schema/views.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Views module.
 
 views.settings:
-  type: mapping
+  type: config_object
   label: 'Views settings'
   mapping:
     display_extenders:
diff --git a/core/themes/stark/config/schema/stark.schema.yml b/core/themes/stark/config/schema/stark.schema.yml
index 03311706e194..2b7f958b7ef9 100644
--- a/core/themes/stark/config/schema/stark.schema.yml
+++ b/core/themes/stark/config/schema/stark.schema.yml
@@ -3,7 +3,3 @@
 stark.settings:
   type: theme_settings
   label: 'Stark settings'
-
-stark.breakpoints:
-  type: theme_breakpoints_default
-  label: 'Stark breakpoints'