diff --git a/core/lib/Drupal/Core/Layout/Annotation/Layout.php b/core/lib/Drupal/Core/Layout/Annotation/Layout.php
index 1cb5ff0..d2072c2 100644
--- a/core/lib/Drupal/Core/Layout/Annotation/Layout.php
+++ b/core/lib/Drupal/Core/Layout/Annotation/Layout.php
@@ -14,11 +14,6 @@
  *
  * Plugin namespace: Plugin\Layout
  *
- * @internal
- *   The layout system is currently experimental and should only be leveraged by
- *   experimental modules and development releases of contributed modules.
- *   See https://www.drupal.org/core/experimental for more information.
- *
  * @see \Drupal\Core\Layout\LayoutInterface
  * @see \Drupal\Core\Layout\LayoutDefault
  * @see \Drupal\Core\Layout\LayoutPluginManager
diff --git a/core/lib/Drupal/Core/Layout/LayoutDefault.php b/core/lib/Drupal/Core/Layout/LayoutDefault.php
index 22edb85..6e53d00 100644
--- a/core/lib/Drupal/Core/Layout/LayoutDefault.php
+++ b/core/lib/Drupal/Core/Layout/LayoutDefault.php
@@ -7,11 +7,6 @@
 
 /**
  * Provides a default class for Layout plugins.
- *
- * @internal
- *   The layout system is currently experimental and should only be leveraged by
- *   experimental modules and development releases of contributed modules.
- *   See https://www.drupal.org/core/experimental for more information.
  */
 class LayoutDefault extends PluginBase implements LayoutInterface {
 
diff --git a/core/lib/Drupal/Core/Layout/LayoutDefinition.php b/core/lib/Drupal/Core/Layout/LayoutDefinition.php
index afbce7e..686cf81 100644
--- a/core/lib/Drupal/Core/Layout/LayoutDefinition.php
+++ b/core/lib/Drupal/Core/Layout/LayoutDefinition.php
@@ -10,11 +10,6 @@
 
 /**
  * Provides an implementation of a layout definition and its metadata.
- *
- * @internal
- *   The layout system is currently experimental and should only be leveraged by
- *   experimental modules and development releases of contributed modules.
- *   See https://www.drupal.org/core/experimental for more information.
  */
 class LayoutDefinition extends PluginDefinition implements PluginDefinitionInterface, DerivablePluginDefinitionInterface, DependentPluginDefinitionInterface {
 
diff --git a/core/lib/Drupal/Core/Layout/LayoutInterface.php b/core/lib/Drupal/Core/Layout/LayoutInterface.php
index bb60df0..32ee74d 100644
--- a/core/lib/Drupal/Core/Layout/LayoutInterface.php
+++ b/core/lib/Drupal/Core/Layout/LayoutInterface.php
@@ -8,11 +8,6 @@
 
 /**
  * Provides an interface for static Layout plugins.
- *
- * @internal
- *   The layout system is currently experimental and should only be leveraged by
- *   experimental modules and development releases of contributed modules.
- *   See https://www.drupal.org/core/experimental for more information.
  */
 interface LayoutInterface extends PluginInspectionInterface, DerivativeInspectionInterface, ConfigurablePluginInterface {
 
diff --git a/core/lib/Drupal/Core/Layout/LayoutPluginManager.php b/core/lib/Drupal/Core/Layout/LayoutPluginManager.php
index e11f105..142b63d 100644
--- a/core/lib/Drupal/Core/Layout/LayoutPluginManager.php
+++ b/core/lib/Drupal/Core/Layout/LayoutPluginManager.php
@@ -15,11 +15,6 @@
 
 /**
  * Provides a plugin manager for layouts.
- *
- * @internal
- *   The layout system is currently experimental and should only be leveraged by
- *   experimental modules and development releases of contributed modules.
- *   See https://www.drupal.org/core/experimental for more information.
  */
 class LayoutPluginManager extends DefaultPluginManager implements LayoutPluginManagerInterface {
 
diff --git a/core/lib/Drupal/Core/Layout/LayoutPluginManagerInterface.php b/core/lib/Drupal/Core/Layout/LayoutPluginManagerInterface.php
index df15be0..c0e606d 100644
--- a/core/lib/Drupal/Core/Layout/LayoutPluginManagerInterface.php
+++ b/core/lib/Drupal/Core/Layout/LayoutPluginManagerInterface.php
@@ -6,11 +6,6 @@
 
 /**
  * Provides the interface for a plugin manager of layouts.
- *
- * @internal
- *   The layout system is currently experimental and should only be leveraged by
- *   experimental modules and development releases of contributed modules.
- *   See https://www.drupal.org/core/experimental for more information.
  */
 interface LayoutPluginManagerInterface extends CategorizingPluginManagerInterface {
 
diff --git a/core/modules/layout_discovery/layout_discovery.info.yml b/core/modules/layout_discovery/layout_discovery.info.yml
index a9a4139..d0c8d3a 100644
--- a/core/modules/layout_discovery/layout_discovery.info.yml
+++ b/core/modules/layout_discovery/layout_discovery.info.yml
@@ -1,6 +1,6 @@
 name: 'Layout Discovery'
 type: module
 description: 'Provides a way for modules or themes to register layouts.'
-package: Core (Experimental)
+package: Core
 version: VERSION
 core: 8.x
diff --git a/core/themes/stable/templates/layout/layout--onecol.html.twig b/core/themes/stable/templates/layout/layout--onecol.html.twig
new file mode 100644
index 0000000..eb553cd
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--onecol.html.twig
@@ -0,0 +1,24 @@
+{#
+/**
+ * @file
+ * Default theme implementation to display a one-column layout.
+ *
+ * Available variables:
+ * - content: The content for this layout.
+ * - attributes: HTML attributes for the layout <div>.
+ *
+ * @ingroup themeable
+ */
+#}
+{%
+set classes = [
+'layout--onecol',
+]
+%}
+{% if content %}
+<div{{ attributes.addClass(classes) }}>
+  <div class="layout-region layout-region--content">
+    {{ content.content }}
+  </div>
+</div>
+{% endif %}
diff --git a/core/themes/stable/templates/layout/layout--threecol-25-50-25.html.twig b/core/themes/stable/templates/layout/layout--threecol-25-50-25.html.twig
new file mode 100644
index 0000000..78db2b4
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--threecol-25-50-25.html.twig
@@ -0,0 +1,47 @@
+{#
+/**
+ * @file
+ * Default theme implementation for a three column layout.
+ *
+ * This template provides a three column 25%-50%-25% display layout, with
+ * additional areas for the top and the bottom.
+ *
+ * Available variables:
+ * - content: The content for this layout.
+ * - attributes: HTML attributes for the layout <div>.
+ *
+ * @ingroup themeable
+ */
+#}
+{%
+set classes = [
+'layout--threecol',
+]
+%}
+{% if content %}
+<div{{ attributes.addClass(classes) }}>
+  {% if content.top %}
+    <div class="layout-region layout-region--fullwidth">
+      {{ content.top }}
+    </div>
+  {% endif %}
+
+  <div class="layout-region layout-region--side">
+    {{ content.left }}
+  </div>
+
+  <div class="layout-region layout-region--middle">
+    {{ content.middle }}
+  </div>
+
+  <div class="layout-region layout-region--side">
+    {{ content.right }}
+  </div>
+
+  {% if content.bottom %}
+    <div class="layout-region layout-region--fullwidth">
+      {{ content.bottom }}
+    </div>
+  {% endif %}
+</div>
+{% endif %}
diff --git a/core/themes/stable/templates/layout/layout--threecol-33-34-33.html.twig b/core/themes/stable/templates/layout/layout--threecol-33-34-33.html.twig
new file mode 100644
index 0000000..59461f4
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--threecol-33-34-33.html.twig
@@ -0,0 +1,47 @@
+{#
+/**
+ * @file
+ * Default theme implementation for a three column layout.
+ *
+ * This template provides a three column 33%-34%-33% display layout, with
+ * additional areas for the top and the bottom.
+ *
+ * Available variables:
+ * - content: The content for this layout.
+ * - attributes: HTML attributes for the layout <div>.
+ *
+ * @ingroup themeable
+ */
+#}
+{%
+set classes = [
+'layout--threecol-33',
+]
+%}
+{% if content %}
+<div{{ attributes.addClass(classes) }}>
+  {% if content.top %}
+  <div class="layout-region layout-region--fullwidth">
+    {{ content.top }}
+  </div>
+  {% endif %}
+
+  <div class="layout-region">
+    {{ content.left }}
+  </div>
+
+  <div class="layout-region">
+    {{ content.middle }}
+  </div>
+
+  <div class="layout-region">
+    {{ content.right }}
+  </div>
+
+  {% if content.bottom %}
+  <div class="layout-region layout-region--fullwidth">
+    {{ content.bottom }}
+  </div>
+  {% endif %}
+</div>
+{% endif %}
diff --git a/core/themes/stable/templates/layout/layout--twocol-bricks.html.twig b/core/themes/stable/templates/layout/layout--twocol-bricks.html.twig
new file mode 100644
index 0000000..9c6231b
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--twocol-bricks.html.twig
@@ -0,0 +1,51 @@
+{#
+/**
+ * @file
+ * Default theme implementation for a two column layout.
+ *
+ * This template provides a two column display layout with full width areas at
+ * the top, bottom and in the middle.
+ *
+ * Available variables:
+ * - content: The content for this layout.
+ * - attributes: HTML attributes for the layout <div>.
+ *
+ * @ingroup themeable
+ */
+#}
+{%
+set classes = [
+'layout--twocol-bricks',
+]
+%}
+{% if content %}
+<div{{ attributes.addClass(classes) }}>
+  <div class="layout-region layout-region--fullwidth">
+    {{ content.top }}
+  </div>
+
+  <div class="layout-region layout-region--left_above">
+    {{ content.left_above }}
+  </div>
+
+  <div class="layout-region layout-region--right_above">
+    {{ content.right_above }}
+  </div>
+
+  <div class="layout-region layout-region--middle">
+    {{ content.middle }}
+  </div>
+
+  <div class="layout-region layout-region--left_below">
+    {{ content.left_below }}
+  </div>
+
+  <div class="layout-region layout-region--right_below">
+    {{ content.right_below }}
+  </div>
+
+  <div class="layout-region layout-region--fullwidth">
+    {{ content.bottom }}
+  </div>
+</div>
+{% endif %}
diff --git a/core/themes/stable/templates/layout/layout--twocol.html.twig b/core/themes/stable/templates/layout/layout--twocol.html.twig
new file mode 100644
index 0000000..efebf0f
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--twocol.html.twig
@@ -0,0 +1,36 @@
+{#
+/**
+ * @file
+ * Default theme implementation to display a two-column layout.
+ *
+ * Available variables:
+ * - content: The content for this layout.
+ * - attributes: HTML attributes for the layout <div>.
+ *
+ * @ingroup themeable
+ */
+#}
+{%
+set classes = [
+'layout--twocol',
+]
+%}
+{% if content %}
+  <div{{ attributes.addClass(classes) }}>
+    <div class="layout-region layout-region--fullwidth">
+      {{ content.top }}
+    </div>
+
+    <div class="layout-region layout-region--left">
+      {{ content.left }}
+    </div>
+
+    <div class="layout-region layout-region--right">
+      {{ content.right }}
+    </div>
+
+    <div class="layout-region layout-region--fullwidth">
+      {{ content.bottom }}
+    </div>
+  </div>
+{% endif %}
diff --git a/core/themes/stable/templates/layout/layout.html.twig b/core/themes/stable/templates/layout/layout.html.twig
new file mode 100644
index 0000000..88ea745
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout.html.twig
@@ -0,0 +1,18 @@
+{#
+/**
+ * @file
+ * Template for a generic layout.
+ */
+#}
+{% set classes = [
+  'layout--' ~ layout.id|clean_class,
+] %}
+{% if content %}
+<div{{ attributes.addClass(classes) }}>
+{% for region in layout.getRegionNames %}
+  <div class="{{ 'region--' ~ region|clean_class }}">
+    {{ content[region] }}
+  </div>
+{% endfor %}
+</div>
+{% endif %}