diff --git a/core/modules/layout_builder/src/LayoutSectionItemInterface.php b/core/modules/layout_builder/src/LayoutSectionItemInterface.php
new file mode 100644
index 0000000..1a39cde
--- /dev/null
+++ b/core/modules/layout_builder/src/LayoutSectionItemInterface.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Drupal\layout_builder;
+
+use Drupal\Core\Field\FieldItemInterface;
+
+/**
+ * Defines an interface for the layout section field item.
+ *
+ * @property string layout
+ * @property array[] section
+ */
+interface LayoutSectionItemInterface extends FieldItemInterface {
+
+}
diff --git a/core/modules/layout_builder/src/Plugin/Field/FieldFormatter/LayoutSectionFormatter.php b/core/modules/layout_builder/src/Plugin/Field/FieldFormatter/LayoutSectionFormatter.php
index 6ef923d..5b07008 100644
--- a/core/modules/layout_builder/src/Plugin/Field/FieldFormatter/LayoutSectionFormatter.php
+++ b/core/modules/layout_builder/src/Plugin/Field/FieldFormatter/LayoutSectionFormatter.php
@@ -4,12 +4,12 @@
 
 use Drupal\Core\Block\BlockManagerInterface;
 use Drupal\Core\Field\FieldDefinitionInterface;
-use Drupal\Core\Field\FieldItemInterface;
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Field\FormatterBase;
-use Drupal\Core\Layout\LayoutPluginManager;
+use Drupal\Core\Layout\LayoutPluginManagerInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\Session\AccountInterface;
+use Drupal\layout_builder\LayoutSectionItemInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -42,21 +42,21 @@ class LayoutSectionFormatter extends FormatterBase implements ContainerFactoryPl
   /**
    * The block plugin manager.
    *
-   * @var BlockManagerInterface
+   * @var \Drupal\Core\Block\BlockManagerInterface
    */
   protected $blockManager;
 
   /**
    * Constructs a LayoutSectionFormatter object.
    *
-   * @param AccountInterface $account
+   * @param \Drupal\Core\Session\AccountInterface $account
    *   The current user.
-   * @param LayoutPluginManager $layoutPluginManager
+   * @param \Drupal\Core\Layout\LayoutPluginManagerInterface $layoutPluginManager
    *   The layout plugin manager.
-   * @param BlockManagerInterface $blockManager
+   * @param \Drupal\Core\Block\BlockManagerInterface $blockManager
    *   THe block plugin manager.
    * @param string $plugin_id
-   *   The plugin_id for the formatter.
+   *   The plugin ID for the formatter.
    * @param mixed $plugin_definition
    *   The plugin implementation definition.
    * @param \Drupal\Core\Field\FieldDefinitionInterface $field_definition
@@ -70,7 +70,7 @@ class LayoutSectionFormatter extends FormatterBase implements ContainerFactoryPl
    * @param array $third_party_settings
    *   Any third party settings.
    */
-  public function __construct(AccountInterface $account, LayoutPluginManager $layoutPluginManager, BlockManagerInterface $blockManager, $plugin_id, $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $view_mode, array $third_party_settings) {
+  public function __construct(AccountInterface $account, LayoutPluginManagerInterface $layoutPluginManager, BlockManagerInterface $blockManager, $plugin_id, $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $view_mode, array $third_party_settings) {
     $this->account = $account;
     $this->layoutPluginManager = $layoutPluginManager;
     $this->blockManager = $blockManager;
@@ -81,7 +81,18 @@ public function __construct(AccountInterface $account, LayoutPluginManager $layo
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
-    return new static($container->get('current_user'), $container->get('plugin.manager.core.layout'), $container->get('plugin.manager.block'), $plugin_id, $plugin_definition, $configuration['field_definition'], $configuration['settings'], $configuration['label'], $configuration['view_mode'], $configuration['third_party_settings']);
+    return new static(
+      $container->get('current_user'),
+      $container->get('plugin.manager.core.layout'),
+      $container->get('plugin.manager.block'),
+      $plugin_id,
+      $plugin_definition,
+      $configuration['field_definition'],
+      $configuration['settings'],
+      $configuration['label'],
+      $configuration['view_mode'],
+      $configuration['third_party_settings']
+    );
   }
 
   /**
@@ -91,26 +102,26 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
     $elements = [];
 
     foreach ($items as $delta => $item) {
-      $elements[$delta] = $this->viewValue($item);
+      $elements[$delta] = $this->buildSection($item);
     }
 
     return $elements;
   }
 
   /**
-   * Build the render array for the field item.
+   * Builds the render array for the layout section.
    *
-   * @param FieldItemInterface $item
-   *   The field item.
+   * @param \Drupal\layout_builder\LayoutSectionItemInterface $item
+   *   The layout section item.
    *
    * @return array
+   *   A render array for the field item.
    */
-  protected function viewValue(FieldItemInterface $item) {
+  protected function buildSection(LayoutSectionItemInterface $item) {
     /** @var \Drupal\Core\Layout\LayoutInterface $layout */
-    $layout = $this->layoutPluginManager->createInstance($item->get('layout')->getValue());
-    $section = $item->get('section')->getValue();
+    $layout = $this->layoutPluginManager->createInstance($item->layout);
     $regions = [];
-    foreach ($section as $region => $blocks) {
+    foreach ($item->section as $region => $blocks) {
       foreach ($blocks as $uuid => $configuration) {
         /** @var \Drupal\Core\Block\BlockPluginInterface $block */
         $block = $this->blockManager->createInstance($configuration['plugin_id'], $configuration);
diff --git a/core/modules/layout_builder/src/Plugin/Field/FieldType/LayoutSection.php b/core/modules/layout_builder/src/Plugin/Field/FieldType/LayoutSectionItem.php
similarity index 92%
rename from core/modules/layout_builder/src/Plugin/Field/FieldType/LayoutSection.php
rename to core/modules/layout_builder/src/Plugin/Field/FieldType/LayoutSectionItem.php
index 9da1937..8cf547d 100644
--- a/core/modules/layout_builder/src/Plugin/Field/FieldType/LayoutSection.php
+++ b/core/modules/layout_builder/src/Plugin/Field/FieldType/LayoutSectionItem.php
@@ -8,6 +8,7 @@
 use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\Core\TypedData\DataDefinition;
 use Drupal\Core\TypedData\MapDataDefinition;
+use Drupal\layout_builder\LayoutSectionItemInterface;
 
 /**
  * Plugin implementation of the 'layout_section' field type.
@@ -19,7 +20,7 @@
  *   default_formatter = "layout_section"
  * )
  */
-class LayoutSection extends FieldItemBase {
+class LayoutSectionItem extends FieldItemBase implements LayoutSectionItemInterface {
 
   /**
    * {@inheritdoc}
@@ -38,7 +39,7 @@ public static function propertyDefinitions(FieldStorageDefinitionInterface $fiel
   }
 
   /**
-   * @inheritDoc
+   * {@inheritdoc}
    */
   public static function mainPropertyName() {
     return 'section';
@@ -60,7 +61,7 @@ public static function schema(FieldStorageDefinitionInterface $field_definition)
           'size' => 'normal',
           'serialize' => TRUE,
         ],
-      ]
+      ],
     ];
 
     return $schema;
diff --git a/core/modules/layout_builder/tests/src/Kernel/LayoutSectionFormatterTest.php b/core/modules/layout_builder/tests/src/Kernel/LayoutSectionFormatterTest.php
new file mode 100644
index 0000000..fe540d0
--- /dev/null
+++ b/core/modules/layout_builder/tests/src/Kernel/LayoutSectionFormatterTest.php
@@ -0,0 +1,120 @@
+<?php
+
+namespace Drupal\Tests\layout_builder\Kernel;
+
+use Drupal\Component\Utility\Unicode;
+use Drupal\Core\Entity\Entity\EntityViewDisplay;
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests the layout section formatter.
+ *
+ * @group layout_builder
+ */
+class LayoutSectionFormatterTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['field', 'layout_builder', 'layout_discovery', 'entity_test', 'user', 'system'];
+
+  /**
+   * The name of the layout section field.
+   *
+   * @var string
+   */
+  protected $fieldName;
+
+  /**
+   * The entity display.
+   *
+   * @var \Drupal\Core\Entity\Display\EntityViewDisplayInterface
+   */
+  protected $display;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->installConfig(['field']);
+    $this->installEntitySchema('entity_test');
+
+    $entity_type = 'entity_test';
+    $bundle = $entity_type;
+    $this->fieldName = Unicode::strtolower($this->randomMachineName());
+
+    $field_storage = FieldStorageConfig::create([
+      'field_name' => $this->fieldName,
+      'entity_type' => $entity_type,
+      'type' => 'layout_section',
+    ]);
+    $field_storage->save();
+
+    $instance = FieldConfig::create([
+      'field_storage' => $field_storage,
+      'bundle' => $bundle,
+      'label' => $this->randomMachineName(),
+    ]);
+    $instance->save();
+
+    $this->display = EntityViewDisplay::create([
+      'targetEntityType' => $entity_type,
+      'bundle' => $bundle,
+      'mode' => 'default',
+      'status' => TRUE,
+    ]);
+    $this->display->setComponent($this->fieldName, [
+      'type' => 'layout_section',
+      'settings' => [],
+    ]);
+    $this->display->save();
+  }
+
+  /**
+   * Tests layout_section formatter output.
+   *
+   * @dataProvider providerTestLayoutSectionFormatter
+   */
+  public function testLayoutSectionFormatter($layout, $section, $expected_selector, $expected_content) {
+    $entity = EntityTest::create([]);
+    $entity->{$this->fieldName}->layout = $layout;
+    $entity->{$this->fieldName}->section = $section;
+
+    // Build and render the content.
+    $content = $this->display->build($entity);
+    $this->render($content);
+
+    // Find the given selector.
+    $element = $this->cssSelect($expected_selector);
+    $this->assertNotEmpty($element);
+
+    // Find the given content.
+    $this->assertRaw($expected_content);
+  }
+
+  /**
+   * Provides test data to ::testLayoutSectionFormatter().
+   */
+  public function providerTestLayoutSectionFormatter() {
+    $data = [];
+    $data[] = [
+      'layout_onecol',
+      [
+        'content' => [
+          'this_should_be_a_UUID' => [
+            'plugin_id' => 'system_powered_by_block',
+          ],
+        ],
+      ],
+      '.layout--onecol',
+      'Powered by',
+    ];
+    return $data;
+  }
+
+}