Added layout sections to configuration screen.

layout_paragraphs.links.menu.yml

-layout_paragraphs.settings:
+layout_paragraphs.label_settings:
   title: 'Layout Paragraphs settings'
+  description: 'Configure site-wide settings for Layout Paragraphs field widgets.'
   parent: system.admin_config_content
-  route_name: layout_paragraphs.settings
+  route_name: layout_paragraphs.label_settings

layout_paragraphs.links.task.yml

+layout_paragraphs.label_settings: # The first plugin ID
+  route_name: layout_paragraphs.label_settings
+  title: 'Labels'
+  base_route: layout_paragraphs.label_settings
+
+layout_paragraphs.section_settings: # The second plugin ID
+  route_name: layout_paragraphs.section_settings
+  title: 'Layout Sections'
+  base_route: layout_paragraphs.label_settings
+  weight: 100
\ No newline at end of file

layout_paragraphs.routing.yml

-layout_paragraphs.settings:
-  path: '/admin/config/content/layout_paragraphs'
+layout_paragraphs.label_settings:
+  path: '/admin/config/content/layout_paragraphs/labels'
   defaults:
     _form: '\Drupal\layout_paragraphs\Form\LayoutParagraphsSettingsForm'
-    _title: 'Layout Paragraphs general settings'
+    _title: 'Layout Paragraphs Labels'
+  requirements:
+    _permission: 'administer site configuration'
+layout_paragraphs.section_settings:
+  path: '/admin/config/content/layout_paragraphs/sections'
+  defaults:
+    _form: '\Drupal\layout_paragraphs\Form\LayoutParagraphsSectionsSettingsForm'
+    _title: 'Layout Paragraphs Sections'
   requirements:
     _permission: 'administer site configuration'

src/Form/LayoutParagraphsSectionsSettingsForm.php

+<?php
+
+namespace Drupal\layout_paragraphs\Form;
+
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Config\TypedConfigManagerInterface;
+use Drupal\Core\Form\ConfigFormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\Core\Entity\EntityTypeBundleInfoInterface;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Layout\LayoutPluginManager;
+
+/**
+ * Class LayoutParagraphsSectionsSettingsForm.
+ */
+class LayoutParagraphsSectionsSettingsForm extends ConfigFormBase {
+
+  /**
+   * The typed config service.
+   *
+   * @var \Drupal\Core\Config\TypedConfigManagerInterface
+   */
+  protected $typedConfigManager;
+
+  /**
+   * The entity type bundle info service.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeBundleInfoInterface
+   */
+  protected $entityTypeBundleInfo;
+
+  /**
+   * The Entity Type Manager service property.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected $entityTypeManager;
+
+  /**
+   * The Layouts Manager.
+   *
+   * @var \Drupal\Core\Layout\LayoutPluginManager
+   */
+  protected $layoutPluginManager;
+
+  /**
+   * SettingsForm constructor.
+   *
+   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+   *   The factory for configuration objects.
+   * @param \Drupal\Core\Config\TypedConfigManagerInterface $typedConfigManager
+   *   The typed config service.
+   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
+   *   The entity type bundle info service.
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+   *   Core entity type manager service.
+   * @param \Drupal\Core\Layout\LayoutPluginManager $layout_plugin_manager
+   *   Core layout plugin manager service.
+   */
+  public function __construct(
+    ConfigFactoryInterface $config_factory,
+    TypedConfigManagerInterface $typedConfigManager,
+    EntityTypeBundleInfoInterface $entity_type_bundle_info,
+    EntityTypeManagerInterface $entity_type_manager,
+    LayoutPluginManager $layout_plugin_manager
+  ) {
+    parent::__construct($config_factory);
+    $this->typedConfigManager = $typedConfigManager;
+    $this->entityTypeBundleInfo = $entity_type_bundle_info;
+    $this->entityTypeManager = $entity_type_manager;
+    $this->layoutPluginManager = $layout_plugin_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('config.factory'),
+      $container->get('config.typed'),
+      $container->get('entity_type.bundle.info'),
+      $container->get('entity_type.manager'),
+      $container->get('plugin.manager.core.layout')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'layout_paragraphs_settings';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getEditableConfigNames() {
+    return [
+      'layout_paragraphs.settings',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $paragraph_bundles = $this->entityTypeBundleInfo->getBundleInfo('paragraph');
+    $form['description'] = [
+      '#type' => 'markup',
+      '#markup' => '<p>' . $this->t('Choose at least one paragraph type to use as a Layout Section.') . '</p>',
+    ];
+    $layout_options = $this->layoutPluginManager->getLayoutOptions();
+    $paragraphs_type_storage = $this->entityTypeManager->getStorage('paragraphs_type');
+    foreach ($paragraph_bundles as $name => $paragraph_bundle) {
+      /** @var \Drupal\paragraphs\Entity\ParagraphsType $paragraphs_type */
+      $paragraphs_type = $paragraphs_type_storage->load($name);
+      $layout_paragraphs_behavior = $paragraphs_type->getBehaviorPlugin('layout_paragraphs');
+      $layout_paragraphs_behavior_config = $layout_paragraphs_behavior->getConfiguration();
+      $form[$name] = [
+        '#type' => 'fieldset',
+        '#title' => $paragraph_bundle['label'],
+        '#description' => $paragraphs_type->getDescription(),
+      ];
+      $form[$name][$name] = [
+        '#type' => 'checkbox',
+        '#title' => $this->t('Use as a Layout Section'),
+        '#default_value' => !empty($layout_paragraphs_behavior_config['enabled']),
+      ];
+      $form[$name][$name . '_layouts'] = [
+        '#type' => 'select',
+        '#title' => $this->t('Available Layouts for @label Paragraphs', ['@label' => $paragraph_bundle['label']]),
+        '#options' => $layout_options,
+        '#multiple' => TRUE,
+        '#default_value' => $layout_paragraphs_behavior_config['available_layouts'],
+        '#size' => count($layout_options) < 8 ? count($layout_options) * 2 : 10,
+        '#states' => [
+          'visible' => [
+            ':input[name="' . $name . '"]' => ['checked' => TRUE],
+          ],
+        ],
+      ];
+    }
+    return parent::buildForm($form, $form_state);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+
+    $paragraph_bundles = $this->entityTypeBundleInfo->getBundleInfo('paragraph');
+    $paragraphs_type_storage = $this->entityTypeManager->getStorage('paragraphs_type');
+    $layouts = $this->layoutPluginManager->getSortedDefinitions();
+    foreach ($paragraph_bundles as $name => $paragraph_bundle) {
+      /** @var \Drupal\paragraphs\Entity\ParagraphsType $paragraphs_type */
+      $paragraphs_type = $paragraphs_type_storage->load($name);
+      $layout_paragraphs_behavior = $paragraphs_type->getBehaviorPlugin('layout_paragraphs');
+      if ($form_state->getValue($name)) {
+        $layout_paragraphs_behavior->setConfiguration(['enabled' => TRUE]);
+        $config = [
+          'enabled' => TRUE,
+          'available_layouts' => [],
+        ];
+        foreach ($form_state->getValue($name . '_layouts') as $layout_id) {
+          $config['available_layouts'][$layout_id] = $layouts[$layout_id]->getLabel();
+        }
+        $layout_paragraphs_behavior->setConfiguration($config);
+      }
+      else {
+        $layout_paragraphs_behavior->setConfiguration(['enabled' => FALSE]);
+      }
+      $paragraphs_type->save();
+    }
+    $this->messenger()->addMessage($this->t('The Layout Paragraphs settings have been saved.'));
+  }
+
+}