diff --git a/core/core.services.yml b/core/core.services.yml
index 6049d3b..e2705fc 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -587,6 +587,9 @@ services:
   plugin.manager.action:
     class: Drupal\Core\Action\ActionManager
     arguments: ['@container.namespaces', '@cache.discovery', '@module_handler']
+  plugin.manager.text_section:
+    class: Drupal\Core\Render\TextSectionManager
+    parent: default_plugin_manager
   plugin.manager.menu.link:
     class: Drupal\Core\Menu\MenuLinkManager
     arguments: ['@menu.tree_storage', '@menu_link.static.overrides', '@module_handler']
diff --git a/core/lib/Drupal/Core/Render/Annotation/TextSection.php b/core/lib/Drupal/Core/Render/Annotation/TextSection.php
new file mode 100644
index 0000000..746f275
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Annotation/TextSection.php
@@ -0,0 +1,57 @@
+<?php
+
+namespace Drupal\Core\Render\Annotation;
+
+use Drupal\Component\Annotation\Plugin;
+
+/**
+ * Defines a Plugin annotation object for a text section.
+ *
+ * See \Drupal\Core\Render\TextSectionPluginInterface for more information
+ * about text sections.
+ *
+ * Plugin Namespace: Plugin\TextSection
+ *
+ * For a working example, see
+ * \Drupal\Core\Render\Plugin\TextSection\Paragraph.
+ *
+ * @see \Drupal\Core\Render\TextSectionPluginInterface
+ * @see \Drupal\Core\Render\Plugin\TextSection\TextSectionBase
+ * @see \Drupal\Core\Render\TextSectionManager
+ * @see \Drupal\Core\Render\Element\TextSections
+ * @see hook_text_section_info_alter()
+ * @see plugin_api
+ *
+ * @Annotation
+ */
+class TextSection extends Plugin {
+
+  /**
+   * The plugin ID.
+   *
+   * @var string
+   */
+  public $id;
+
+  /**
+   * The human-readable label for the text section.
+   *
+   * @var \Drupal\Core\Annotation\Translation
+   *
+   * @ingroup plugin_translatable
+   */
+  public $label;
+
+  /**
+   * The sort order weight of this section type.
+   *
+   * Lower numbers come first, and an alphabetical sort by label will be used
+   * for same-weighted plugins.
+   *
+   * @var int
+   *
+   * @see \Drupal\Core\Render\TextSectionManager::sortPlugins()
+   */
+  public $weight = 0;
+
+}
diff --git a/core/lib/Drupal/Core/Render/Element/TextSections.php b/core/lib/Drupal/Core/Render/Element/TextSections.php
new file mode 100644
index 0000000..a0a3d35
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Element/TextSections.php
@@ -0,0 +1,130 @@
+<?php
+
+namespace Drupal\Core\Render\Element;
+
+/**
+ * Provides a text sections render element.
+ *
+ * This provides a way to specify a piece of text with markup in "sections",
+ * such as paragraphs, bullet list items, headers, etc. Compatible sections
+ * will be grouped; for example, consecutive bullet list items will be grouped
+ * into a bullet list.
+ *
+ * Properties:
+ * - #sections: Array of sections to include, each of which is an array with
+ *   the following elements:
+ *   - #section_type: The plugin ID of a TextSection plugin. See
+ *     \Drupal\Core\Render\TextSectionPluginInterface for more information.
+ *   - #text: A render array for the text to go in this section.
+ *
+ * Usage example:
+ * @code
+ * $build['body'] = [
+ *   '#type' => 'text_sections',
+ *   '#sections' => [
+ *     [
+ *       '#section_type' => 'heading',
+ *       '#text' => ['#markup' => t('Greetings')],
+ *     ],
+ *     [
+ *       '#section_type' => 'paragraph',
+ *       '#text' => ['#markup' => t('Hello, world.')],
+ *     ],
+ *   ],
+ * ];
+ * @endcode
+ *
+ * @see \Drupal\Core\Render\TextSectionPluginInterface
+ *
+ * @RenderElement("text_sections")
+ */
+class TextSections extends RenderElement {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInfo() {
+    $class = get_class($this);
+    return [
+      '#pre_render' => [[$class, 'preRenderSections']],
+    ];
+  }
+
+  /**
+   * Expands a #text_sections element into an array of sections.
+   *
+   * @param array $element
+   *   The form element to process. See main class documentation for properties.
+   *
+   * @return array
+   *   The form element.
+   */
+  public static function preRenderSections(&$element) {
+    // Iterate through the provided sections, adding each as a new render
+    // array child to $element, or as part of a grouped render array.
+    $sections = $element['#sections'];
+    unset($element['#sections']);
+    unset($element['#type']);
+    $manager = self::sectionManager();
+    $element['text_sections'] = [];
+
+    $previous_type = '';
+    $group_build = [];
+
+    /** @var \Drupal\Core\Render\RendererInterface $renderer */
+    $renderer = \Drupal::service('renderer');
+    foreach ($sections as $section) {
+      /** @var \Drupal\Core\Render\TextSectionPluginInterface $plugin */
+      $plugin = $manager->createInstance($section['#section_type']);
+      if (!$plugin) {
+        // Do not attempt to render unknown types. Just skip them.
+        continue;
+      }
+
+      // Set up the inner build.
+      $renderer->addCacheableDependency($element, $plugin);
+      $plugin->setText($section['#text']);
+
+      // Check for grouping.
+      $this_group_with = $plugin->groupWith();
+
+      if (!in_array($previous_type, $this_group_with) && !empty($group_build)) {
+        // This section should not be grouped with the previous one, so add the
+        // previous grouping to the element and reset the in-progress group.
+        $element['text_sections'][] = $group_build;
+        $group_build = [];
+      }
+
+      if (!empty($this_group_with)) {
+        // This is a grouped section, either for a new group or a compatible
+        // group. Add this to the group, or initialize a new group.
+        $group_build = $plugin->addToGroup($group_build);
+      }
+      else {
+        // It is not grouped, so just add it to the element.
+        $element['text_sections'][] = $plugin->getInnerBuild();
+      }
+
+      // Save this type for the next grouping decision.
+      $previous_type = $section['#section_type'];
+    }
+
+    // Add the last in-progress group to the element if there is one.
+    if (!empty($group_build)) {
+      $element['text_sections'][] = $group_build;
+    }
+
+    return $element;
+  }
+
+  /**
+   * Wraps the text section manager service.
+   *
+   * @return \Drupal\Core\Render\TextSectionManager
+   *   The text section plugin manager.
+   */
+  protected static function sectionManager() {
+    return \Drupal::service('plugin.manager.text_section');
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/Plugin/TextSection/BulletItem.php b/core/lib/Drupal/Core/Render/Plugin/TextSection/BulletItem.php
new file mode 100644
index 0000000..3dd9aaf
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Plugin/TextSection/BulletItem.php
@@ -0,0 +1,39 @@
+<?php
+
+namespace Drupal\Core\Render\Plugin\TextSection;
+
+/**
+ * Provides a text section for a bullet list item.
+ *
+ * @TextSection(
+ *   id = "bullet",
+ *   label = @Translation("Bullet list item"),
+ *   weight = -10
+ * )
+ */
+class BulletItem extends TextSectionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function groupWith() {
+    return ['bullet'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function addToGroup(array $group) {
+    // Initialize the group, in case this is the first item.
+    $group += [
+      '#theme' => 'item_list',
+      '#list_type' => 'ul',
+      '#items' => [],
+    ];
+
+    $group['#items'][] = $this->getInnerBuild();
+
+    return $group;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/Plugin/TextSection/Code.php b/core/lib/Drupal/Core/Render/Plugin/TextSection/Code.php
new file mode 100644
index 0000000..53a526d
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Plugin/TextSection/Code.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\Core\Render\Plugin\TextSection;
+
+/**
+ * Provides a code text section.
+ *
+ * @TextSection(
+ *   id = "code",
+ *   label = @Translation("Code"),
+ *   weight = 100
+ * )
+ */
+class Code extends TextSectionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInnerBuild() {
+    return [
+      '#prefix' => '<pre><code>',
+      '#suffix' => '</code></pre>',
+    ] + parent::getInnerBuild();
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/Plugin/TextSection/DescriptionName.php b/core/lib/Drupal/Core/Render/Plugin/TextSection/DescriptionName.php
new file mode 100644
index 0000000..3a29c90
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Plugin/TextSection/DescriptionName.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace Drupal\Core\Render\Plugin\TextSection;
+
+/**
+ * Provides a text section for a name item in a description list.
+ *
+ * This is normally rendered as a DT element in a DL list, in HTML.
+ *
+ * @see Drupal\Core\Render\Plugin\DescriptionValue
+ *
+ * @TextSection(
+ *   id = "description_name",
+ *   label = @Translation("Description list name item"),
+ *   weight = 10
+ * )
+ */
+class DescriptionName extends TextSectionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInnerBuild() {
+    return [
+      '#prefix' => '<dt>',
+      '#suffix' => '</dt>',
+    ] + parent::getInnerBuild();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function groupWith() {
+    return ['description_name', 'description_value'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function addToGroup(array $group) {
+    // Initialize the group, in case this is the first item.
+    $group += [
+      '#prefix' => '<dl>',
+      '#suffix' => '</dl>',
+      'list' => [],
+    ];
+
+    $group['list'][] = $this->getInnerBuild();
+
+    return $group;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/Plugin/TextSection/DescriptionValue.php b/core/lib/Drupal/Core/Render/Plugin/TextSection/DescriptionValue.php
new file mode 100644
index 0000000..047f08e
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Plugin/TextSection/DescriptionValue.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace Drupal\Core\Render\Plugin\TextSection;
+
+/**
+ * Provides a text section for a value item in a description list.
+ *
+ * This is normally rendered as a DD element in a DL list, in HTML.
+ *
+ * @see Drupal\Core\Render\Plugin\DescriptionName
+ *
+ * @TextSection(
+ *   id = "description_value",
+ *   label = @Translation("Description list value item"),
+ *   weight = 11
+ * )
+ */
+class DescriptionValue extends TextSectionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInnerBuild() {
+    return [
+      '#prefix' => '<dd>',
+      '#suffix' => '</dd>',
+    ] + parent::getInnerBuild();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function groupWith() {
+    return ['description_name', 'description_value'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function addToGroup(array $group) {
+    // Initialize the group, in case this is the first item.
+    $group += [
+      '#prefix' => '<dl>',
+      '#suffix' => '</dl>',
+      'list' => [],
+    ];
+
+    $group['list'][] = $this->getInnerBuild();
+
+    return $group;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/Plugin/TextSection/Heading.php b/core/lib/Drupal/Core/Render/Plugin/TextSection/Heading.php
new file mode 100644
index 0000000..7855aab
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Plugin/TextSection/Heading.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\Core\Render\Plugin\TextSection;
+
+/**
+ * Provides a text section for a heading.
+ *
+ * @TextSection(
+ *   id = "heading",
+ *   label = @Translation("Heading"),
+ *   weight = -20
+ * )
+ */
+class Heading extends TextSectionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInnerBuild() {
+    return [
+      '#prefix' => '<h2>',
+      '#suffix' => '</h2>',
+    ] + parent::getInnerBuild();
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/Plugin/TextSection/NumberedItem.php b/core/lib/Drupal/Core/Render/Plugin/TextSection/NumberedItem.php
new file mode 100644
index 0000000..7701ee2
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Plugin/TextSection/NumberedItem.php
@@ -0,0 +1,39 @@
+<?php
+
+namespace Drupal\Core\Render\Plugin\TextSection;
+
+/**
+ * Provides a text section for a numbered list item.
+ *
+ * @TextSection(
+ *   id = "numbered",
+ *   label = @Translation("Numbered list item"),
+ *   weight = -10
+ * )
+ */
+class NumberedItem extends TextSectionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function groupWith() {
+    return ['numbered'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function addToGroup(array $group) {
+    // Initialize the group, in case this is the first item.
+    $group += [
+      '#theme' => 'item_list',
+      '#list_type' => 'ol',
+      '#items' => [],
+    ];
+
+    $group['#items'][] = $this->getInnerBuild();
+
+    return $group;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/Plugin/TextSection/Paragraph.php b/core/lib/Drupal/Core/Render/Plugin/TextSection/Paragraph.php
new file mode 100644
index 0000000..ee1d821
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Plugin/TextSection/Paragraph.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\Core\Render\Plugin\TextSection;
+
+/**
+ * Provides a paragraph text section.
+ *
+ * @TextSection(
+ *   id = "paragraph",
+ *   label = @Translation("Paragraph"),
+ *   weight = -100
+ * )
+ */
+class Paragraph extends TextSectionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInnerBuild() {
+    return [
+      '#prefix' => '<p>',
+      '#suffix' => '</p>',
+    ] + parent::getInnerBuild();
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/Plugin/TextSection/SubHeading.php b/core/lib/Drupal/Core/Render/Plugin/TextSection/SubHeading.php
new file mode 100644
index 0000000..626c00a
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Plugin/TextSection/SubHeading.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\Core\Render\Plugin\TextSection;
+
+/**
+ * Provides a text section for a sub-heading.
+ *
+ * @TextSection(
+ *   id = "subheading",
+ *   label = @Translation("Sub-heading"),
+ *   weight = -19
+ * )
+ */
+class SubHeading extends TextSectionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInnerBuild() {
+    return [
+      '#prefix' => '<h3>',
+      '#suffix' => '</h3>',
+    ] + parent::getInnerBuild();
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/Plugin/TextSection/TextSectionBase.php b/core/lib/Drupal/Core/Render/Plugin/TextSection/TextSectionBase.php
new file mode 100644
index 0000000..cff171d
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/Plugin/TextSection/TextSectionBase.php
@@ -0,0 +1,55 @@
+<?php
+
+namespace Drupal\Core\Render\Plugin\TextSection;
+
+use Drupal\Core\Plugin\PluginBase;
+use Drupal\Core\Render\TextSectionPluginInterface;
+
+/**
+ * Provides a base class for text section plugins.
+ *
+ * @see \Drupal\help\HelpSectionPluginInterface
+ * @see \Drupal\help\Annotation\HelpSection
+ * @see \Drupal\help\HelpSectionManager
+ */
+abstract class TextSectionBase extends PluginBase implements TextSectionPluginInterface {
+
+  /**
+   * The inner text for this section.
+   *
+   * @var array
+   */
+  protected $text;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setText($text) {
+    if (!is_array($text)) {
+      $text = ['#markup' => $text];
+    }
+    $this->text = $text;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInnerBuild() {
+    return $this->text;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function groupWith() {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function addToGroup(array $group) {
+    return [];
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/TextSectionManager.php b/core/lib/Drupal/Core/Render/TextSectionManager.php
new file mode 100644
index 0000000..1c52772
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/TextSectionManager.php
@@ -0,0 +1,95 @@
+<?php
+
+namespace Drupal\Core\Render;
+
+use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Plugin\DefaultPluginManager;
+
+/**
+ * Manages text section plugins.
+ *
+ * @see \Drupal\Core\Render\TextSectionPluginInterface
+ * @see \Drupal\Core\Render\Plugin\TextSection\TextSectionBase
+ * @see \Drupal\Core\Render\Annotation\TextSection
+ * @see hook_text_section_info_alter()
+ */
+class TextSectionManager extends DefaultPluginManager {
+
+  /**
+   * Constructs a new TextSectionManager.
+   *
+   * @param \Traversable $namespaces
+   *   An object that implements \Traversable which contains the root paths
+   *   keyed by the corresponding namespace to look for plugin implementations.
+   * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
+   *   Cache backend instance to use.
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   The module handler for the alter hook.
+   */
+  public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
+    parent::__construct('Plugin/TextSection', $namespaces, $module_handler, 'Drupal\Core\Render\TextSectionPluginInterface', 'Drupal\Core\Render\Annotation\TextSection');
+
+    $this->alterInfo('text_section_info');
+    $this->setCacheBackend($cache_backend, 'text_section_plugins');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function findDefinitions() {
+    $definitions = parent::findDefinitions();
+    uasort($definitions, [$this, 'sortPlugins']);
+    return $definitions;
+  }
+
+  /**
+   * Makes an options array for a select list of text section plugins.
+   *
+   * @return array
+   *   Array whose keys are machine names of text section plugins, and whose
+   *   values are the translated labels for the plugins, suitable for use as
+   *   options for radios or select lists.
+   */
+  public function getOptionsList() {
+    $plugins = $this->getDefinitions();
+    $options = [];
+    foreach ($plugins as $plugin_id => $plugin_definition) {
+      $options[$plugin_id] = $plugin_definition['label'];
+    }
+
+    return $options;
+  }
+
+  /**
+   * Provides a uasort() callback for sorting plugin definitions.
+   *
+   * Sorts by weight first, and within the same weight, alphabetically by
+   * label.
+   *
+   * @param array $definition1
+   *   First plugin definition to compare.
+   * @param array $definition2
+   *   Second plugin definition to compare.
+   *
+   * @return int
+   *   A number <1 if the first plugin should come first, >1 if the second
+   *   should, and 0 if this cannot be determined.
+   */
+  protected function sortPlugins($definition1, $definition2) {
+    if ($definition1['weight'] < $definition2['weight']) {
+      return -1;
+    }
+    if ($definition2['weight'] < $definition1['weight']) {
+      return 1;
+    }
+    if ($definition1['label'] < $definition2['label']) {
+      return -1;
+    }
+    if ($definition2['label'] < $definition1['label']) {
+      return 1;
+    }
+    return 0;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/TextSectionPluginInterface.php b/core/lib/Drupal/Core/Render/TextSectionPluginInterface.php
new file mode 100644
index 0000000..10449f0
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/TextSectionPluginInterface.php
@@ -0,0 +1,77 @@
+<?php
+
+namespace Drupal\Core\Render;
+
+use Drupal\Component\Plugin\PluginInspectionInterface;
+
+/**
+ * Provides an interface defining a plugin for a simple text section.
+ *
+ * Text sections are wrappers for text that abstract away the exact markup
+ * needed for the text. Examples include paragraphs, headers, and bullet list
+ * items.
+ *
+ * They can optionally be grouped; for instance, consecutive bullet list items
+ * would normally be grouped together into one bullet list.
+ *
+ * Plugins of this type need to be annotated with
+ * \Drupal\Core\Render\Annotation\TextSection annotation, and placed in the
+ * Plugin\TextSection namespace directory. They are managed by the
+ * \Drupal\Core\Render\TextSectionManager plugin manager class. There is also
+ * a base class that may be helpful:
+ * \Drupal\Core\Render\Plugin\TextSection\TextSectionBase. To use text sections
+ * in render arrays, see \Drupal\Core\Render\Element\TextSections.
+ */
+interface TextSectionPluginInterface extends PluginInspectionInterface {
+
+  /**
+   * Sets the text to put into this section.
+   *
+   * @param array|string $text
+   *   A render array, string, or object that can be cast to string,
+   *   representing the text that this section should contain.
+   */
+  public function setText($text);
+
+  /**
+   * Returns the render array for this section.
+   *
+   * This doesn't include any grouping, so it is just the render array for
+   * one item of a grouped section.
+   *
+   * @return array
+   *   Render array containing the text set by self::setText(), and any
+   *   wrappers and render element properties needed to render it as this type
+   *   of section.
+   */
+  public function getInnerBuild();
+
+  /**
+   * Determines which types this section should be grouped with.
+   *
+   * For example, bullet list items should be grouped together with other
+   * consecutive bullet list items, but not with numbered list items.
+   *
+   * @return string[]
+   *   A list of the plugin IDs of section types that this section should be
+   *   grouped with. Return an empty array if this is not a grouped section.
+   */
+  public function groupWith();
+
+  /**
+   * Adds this item to a group.
+   *
+   * Call this after self::setText() has been called to set the inner text.
+   *
+   * @param array $group
+   *   The previous render array for the group. May be empty to initialize
+   *   a new group. Assumes that the group contains only items that are of
+   *   compatible types, as returned by self::groupWith().
+   *
+   * @return array
+   *   A render array for the group, including items previously in $group and
+   *   the item defined by this section.
+   */
+  public function addToGroup(array $group);
+
+}
diff --git a/core/lib/Drupal/Core/Render/theme.api.php b/core/lib/Drupal/Core/Render/theme.api.php
index 19a7038..db72432 100644
--- a/core/lib/Drupal/Core/Render/theme.api.php
+++ b/core/lib/Drupal/Core/Render/theme.api.php
@@ -1276,5 +1276,25 @@ function hook_template_preprocess_default_variables_alter(&$variables) {
 }
 
 /**
+ * Perform alterations on text section plugin definitions.
+ *
+ * Sections (such as paragraphs, headers, and list items) that can be used
+ * in textual items (such as configurable help topics) are provided by plugins.
+ * This hook allows modules to alter the plugin definitions.
+ *
+ * @param array $info
+ *   Array of plugin information exposed by text section plugins, altered by
+ *   reference.
+ *
+ * @see \Drupal\Core\Render\TextSectionPluginInterface
+ * @see \Drupal\Core\Render\Annotation\TextSection
+ * @see \Drupal\Core\Render\TextSectionManager
+ */
+function hook_text_section_info_alter(&$info) {
+  // Alter the label for the bullet list item plugin.
+  $info['bullet']['label'] = t('Unordered list item');
+}
+
+/**
  * @} End of "addtogroup hooks".
  */
diff --git a/core/modules/help/help.module b/core/modules/help/help.module
index c41cd98..4a94d2d 100644
--- a/core/modules/help/help.module
+++ b/core/modules/help/help.module
@@ -14,32 +14,84 @@
 function help_help($route_name, RouteMatchInterface $route_match) {
   switch ($route_name) {
     case 'help.main':
-      $output = '<h2>' . t('Getting Started') . '</h2>';
-      $output .= '<p>' . t('Follow these steps to set up and start using your website:') . '</p>';
-      $output .= '<ol>';
-      $output .= '<li>' . t('<strong>Configure your website</strong> Once logged in, visit the <a href=":admin">Administration page</a>, where you may <a href=":config">customize and configure</a> all aspects of your website.', array(':admin' => \Drupal::url('system.admin'), ':config' => \Drupal::url('system.admin_config'))) . '</li>';
-      $output .= '<li>' . t('<strong>Enable additional functionality</strong> Next, visit the <a href=":modules">Extend page</a> and enable modules that suit your specific needs. You can find additional modules at the <a href=":download_modules">Drupal.org modules page</a>.', array(':modules' => \Drupal::url('system.modules_list'), ':download_modules' => 'https://www.drupal.org/project/modules')) . '</li>';
-      $output .= '<li>' . t('<strong>Customize your website design</strong> To change the "look and feel" of your website, visit the <a href=":themes">Appearance page</a>. You may choose from one of the included themes or download additional themes from the <a href=":download_themes">Drupal.org themes page</a>.', array(':themes' => \Drupal::url('system.themes_page'), ':download_themes' => 'https://www.drupal.org/project/themes')) . '</li>';
+      $sections = [];
+      $sections[] = [
+        '#section_type' => 'heading',
+        '#text' => t('Getting Started'),
+      ];
+      $sections[] = [
+        '#section_type' => 'paragraph',
+        '#text' => t('Follow these steps to set up and start using your website:'),
+      ];
+      $sections[] = [
+        '#section_type' => 'numbered',
+        '#text' => t('<strong>Configure your website</strong> Once logged in, visit the <a href=":admin">Administration page</a>, where you may <a href=":config">customize and configure</a> all aspects of your website.', array(':admin' => \Drupal::url('system.admin'), ':config' => \Drupal::url('system.admin_config'))),
+      ];
+      $sections[] = [
+        '#section_type' => 'numbered',
+        '#text' => t('<strong>Enable additional functionality</strong> Next, visit the <a href=":modules">Extend page</a> and enable modules that suit your specific needs. You can find additional modules at the <a href=":download_modules">Drupal.org modules page</a>.', array(':modules' => \Drupal::url('system.modules_list'), ':download_modules' => 'https://www.drupal.org/project/modules')),
+      ];
+      $sections[] = [
+        '#section_type' => 'numbered',
+        '#text' => t('<strong>Customize your website design</strong> To change the "look and feel" of your website, visit the <a href=":themes">Appearance page</a>. You may choose from one of the included themes or download additional themes from the <a href=":download_themes">Drupal.org themes page</a>.', array(':themes' => \Drupal::url('system.themes_page'), ':download_themes' => 'https://www.drupal.org/project/themes')),
+      ];
+
       // Display a link to the create content page if Node module is enabled.
       if (\Drupal::moduleHandler()->moduleExists('node')) {
-        $output .= '<li>' . t('<strong>Start posting content</strong> Finally, you may <a href=":content">add new content</a> to your website.', array(':content' => \Drupal::url('node.add_page'))) . '</li>';
+        $sections[] = [
+          '#section_type' => 'numbered',
+          '#text' => t('<strong>Start posting content</strong> Finally, you may <a href=":content">add new content</a> to your website.', array(':content' => \Drupal::url('node.add_page'))),
+        ];
       }
-      $output .= '</ol>';
-      $output .= '<p>' . t('For more information, refer to the help listed on this page or to the <a href=":docs">online documentation</a> and <a href=":support">support</a> pages at <a href=":drupal">drupal.org</a>.', array(':docs' => 'https://www.drupal.org/documentation', ':support' => 'https://www.drupal.org/support', ':drupal' => 'https://www.drupal.org')) . '</p>';
-      return ['#markup' => $output];
+      $sections[] = [
+        '#section_type' => 'paragraph',
+        '#text' => t('For more information, refer to the help listed on this page or to the <a href=":docs">online documentation</a> and <a href=":support">support</a> pages at <a href=":drupal">drupal.org</a>.', array(':docs' => 'https://www.drupal.org/documentation', ':support' => 'https://www.drupal.org/support', ':drupal' => 'https://www.drupal.org')),
+      ];
+
+      $build = [
+        '#type' => 'text_sections',
+        '#sections' => $sections,
+      ];
+
+      return [$build];
 
     case 'help.page.help':
-      $output = '';
-      $output .= '<h3>' . t('About') . '</h3>';
-      $output .= '<p>' . t('The Help module generates <a href=":help-page">Help reference pages</a> to guide you through the use and configuration of modules, and provides a Help block with page-level help. The reference pages are a starting point for <a href=":handbook">Drupal.org online documentation</a> pages that contain more extensive and up-to-date information, are annotated with user-contributed comments, and serve as the definitive reference point for all Drupal documentation. For more information, see the <a href=":help">online documentation for the Help module</a>.', array(':help' => 'https://www.drupal.org/documentation/modules/help/', ':handbook' => 'https://www.drupal.org/documentation', ':help-page' => \Drupal::url('help.main'))) . '</p>';
-      $output .= '<h3>' . t('Uses') . '</h3>';
-      $output .= '<dl>';
-      $output .= '<dt>' . t('Providing a help reference') . '</dt>';
-      $output .= '<dd>' . t('The Help module displays explanations for using each module listed on the main <a href=":help">Help reference page</a>.', array(':help' => \Drupal::url('help.main'))) . '</dd>';
-      $output .= '<dt>' . t('Providing page-specific help') . '</dt>';
-      $output .= '<dd>' . t('Page-specific help text provided by modules is displayed in the Help block. This block can be placed and configured on the <a href=":blocks">Block layout page</a>.', array(':blocks' => (\Drupal::moduleHandler()->moduleExists('block')) ? \Drupal::url('block.admin_display') : '#')) . '</dd>';
-      $output .= '</dl>';
-      return ['#markup' => $output];
+      $sections = [];
+      $sections[] = [
+        '#section_type' => 'subheading',
+        '#text' => t('About'),
+      ];
+      $sections[] = [
+        '#section_type' => 'paragraph',
+        '#text' => t('The Help module generates <a href=":help-page">Help reference pages</a> to guide you through the use and configuration of modules, and provides a Help block with page-level help. The reference pages are a starting point for <a href=":handbook">Drupal.org online documentation</a> pages that contain more extensive and up-to-date information, are annotated with user-contributed comments, and serve as the definitive reference point for all Drupal documentation. For more information, see the <a href=":help">online documentation for the Help module</a>.', array(':help' => 'https://www.drupal.org/documentation/modules/help/', ':handbook' => 'https://www.drupal.org/documentation', ':help-page' => \Drupal::url('help.main'))),
+      ];
+      $sections[] = [
+        '#section_type' => 'subheading',
+        '#text' => t('Uses'),
+      ];
+      $sections[] = [
+        '#section_type' => 'description_name',
+        '#text' => t('Providing a help reference'),
+      ];
+      $sections[] = [
+        '#section_type' => 'description_value',
+        '#text' => t('The Help module displays explanations for using each module listed on the main <a href=":help">Help reference page</a>.', array(':help' => \Drupal::url('help.main'))),
+      ];
+      $sections[] = [
+        '#section_type' => 'description_name',
+        '#text' => t('Providing page-specific help'),
+      ];
+      $sections[] = [
+        '#section_type' => 'description_value',
+        '#text' => t('Page-specific help text provided by modules is displayed in the Help block. This block can be placed and configured on the <a href=":blocks">Block layout page</a>.', array(':blocks' => (\Drupal::moduleHandler()->moduleExists('block')) ? \Drupal::url('block.admin_display') : '#')),
+      ];
+
+      $build = [
+        '#type' => 'text_sections',
+        '#sections' => $sections,
+      ];
+
+      return $build;
   }
 }
 
diff --git a/core/tests/Drupal/KernelTests/Core/Render/TextSectionRenderingTest.php b/core/tests/Drupal/KernelTests/Core/Render/TextSectionRenderingTest.php
new file mode 100644
index 0000000..1605f99
--- /dev/null
+++ b/core/tests/Drupal/KernelTests/Core/Render/TextSectionRenderingTest.php
@@ -0,0 +1,218 @@
+<?php
+
+namespace Drupal\KernelTests\Core\Render;
+
+use Drupal\KernelTests\KernelTestBase;
+use Drupal\Core\Render\Element\TextSections;
+
+/**
+ * Tests the functionality of the TextSection plugins, via the render element.
+ *
+ * This cannot be a PHPUnit test, because the TextSections render element
+ * needs the text_section plugin manager, and it gets this via a static
+ * method. Static methods cannot be stubbed in PHPUnit. So this has to be a
+ * KernelTestBase test instead.
+ *
+ * @group render
+ */
+class TextSectionRenderingTest extends KernelTestBase {
+
+  /**
+   * Tests conversion of text sections into a more basic render array.
+   */
+  public function testPreRenderSections() {
+    // Make a render array with all of the existing text section plugins,
+    // some with #markup and some with plain strings in #text.
+    $element = [
+      '#type' => 'text_sections',
+      '#sections' => [
+        [
+          '#section_type' => 'heading',
+          '#text' => ['#markup' => 'First H2 header'],
+        ],
+        [
+          '#section_type' => 'heading',
+          '#text' => 'Second H2 header',
+        ],
+        [
+          '#section_type' => 'subheading',
+          '#text' => ['#markup' => 'First H3 sub-header'],
+        ],
+        [
+          '#section_type' => 'subheading',
+          '#text' => 'Second H3 sub-header',
+        ],
+        [
+          '#section_type' => 'paragraph',
+          '#text' => 'First paragraph',
+        ],
+        [
+          '#section_type' => 'paragraph',
+          '#text' => ['#markup' => 'Second paragraph'],
+        ],
+        [
+          '#section_type' => 'code',
+          '#text' => 'Some code',
+        ],
+        [
+          '#section_type' => 'code',
+          '#text' => ['#markup' => 'More code'],
+        ],
+        [
+          '#section_type' => 'bullet',
+          '#text' => ['#markup' => 'First list, first bullet'],
+        ],
+        [
+          '#section_type' => 'bullet',
+          '#text' => 'First list, second bullet',
+        ],
+        [
+          '#section_type' => 'numbered',
+          '#text' => ['#markup' => 'Numbered list, first item'],
+        ],
+        [
+          '#section_type' => 'numbered',
+          '#text' => 'Numbered list, second item',
+        ],
+        [
+          '#section_type' => 'description_name',
+          '#text' => 'DL list, first name',
+        ],
+        [
+          '#section_type' => 'description_value',
+          '#text' => 'DL list, first value',
+        ],
+        [
+          '#section_type' => 'description_name',
+          '#text' => ['#markup' => 'DL list, second name'],
+        ],
+        [
+          '#section_type' => 'description_value',
+          '#text' => ['#markup' => 'DL list, second value'],
+        ],
+      ],
+    ];
+
+    // Pre-render the element into a more basic render array.
+    $result = TextSections::preRenderSections($element);
+
+    // Compare to the expected result, but only the text_sections part.
+    $expected = [
+      [
+        '#prefix' => '<h2>',
+        '#suffix' => '</h2>',
+        '#markup' => 'First H2 header',
+      ],
+      [
+        '#prefix' => '<h2>',
+        '#suffix' => '</h2>',
+        '#markup' => 'Second H2 header',
+      ],
+      [
+        '#prefix' => '<h3>',
+        '#suffix' => '</h3>',
+        '#markup' => 'First H3 sub-header',
+      ],
+      [
+        '#prefix' => '<h3>',
+        '#suffix' => '</h3>',
+        '#markup' => 'Second H3 sub-header',
+      ],
+      [
+        '#prefix' => '<p>',
+        '#suffix' => '</p>',
+        '#markup' => 'First paragraph',
+      ],
+      [
+        '#prefix' => '<p>',
+        '#suffix' => '</p>',
+        '#markup' => 'Second paragraph',
+      ],
+      [
+        '#prefix' => '<pre><code>',
+        '#suffix' => '</code></pre>',
+        '#markup' => 'Some code',
+      ],
+      [
+        '#prefix' => '<pre><code>',
+        '#suffix' => '</code></pre>',
+        '#markup' => 'More code',
+      ],
+      [
+        '#theme' => 'item_list',
+        '#list_type' => 'ul',
+        '#items' => [
+          ['#markup' => 'First list, first bullet'],
+          ['#markup' => 'First list, second bullet'],
+        ],
+      ],
+      [
+        '#theme' => 'item_list',
+        '#list_type' => 'ol',
+        '#items' => [
+          ['#markup' => 'Numbered list, first item'],
+          ['#markup' => 'Numbered list, second item'],
+        ],
+      ],
+      [
+        '#prefix' => '<dl>',
+        '#suffix' => '</dl>',
+        'list' => [
+          [
+            '#prefix' => '<dt>',
+            '#suffix' => '</dt>',
+            '#markup' => 'DL list, first name',
+          ],
+          [
+            '#prefix' => '<dd>',
+            '#suffix' => '</dd>',
+            '#markup' => 'DL list, first value',
+          ],
+          [
+            '#prefix' => '<dt>',
+            '#suffix' => '</dt>',
+            '#markup' => 'DL list, second name',
+          ],
+          [
+            '#prefix' => '<dd>',
+            '#suffix' => '</dd>',
+            '#markup' => 'DL list, second value',
+          ],
+        ],
+      ]];
+
+    $this->assertTrue($result['text_sections'] == $expected, 'Pre-processing behaved as expected');
+  }
+
+  /**
+   * Tests the options list for text sections.
+   */
+  public function testOptionsList() {
+    /** @var \Drupal\Core\Render\TextSectionManager $manager */
+    $manager = \Drupal::service('plugin.manager.text_section');
+    $options = $manager->getOptionsList();
+
+    // The sorting of the list should be by weight first, then alphabetically
+    // by label.
+    $expected = [
+      // Weight is -100.
+      'paragraph' => 'Paragraph',
+      // Weight is -20.
+      'heading' => 'Heading',
+      // Weight is -19.
+      'subheading' => 'Sub-heading',
+      // Weight is -10.
+      'bullet' => 'Bullet list item',
+      'numbered' => 'Numbered list item',
+      // Weight is 10.
+      'description_name' => 'Description list name item',
+      // Weight is 11.
+      'description_value' => 'Description list value item',
+      // Weight is 100.
+      'code' => 'Code',
+    ];
+
+    $this->assertTrue($options == $expected, 'Options list was as expected');
+  }
+
+}