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 0a28785..179d1ed 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..64b9b4e
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--onecol.html.twig
@@ -0,0 +1,25 @@
+{#
+/**
+ * @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',
+    '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..8525525
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--threecol-25-50-25.html.twig
@@ -0,0 +1,54 @@
+{#
+/**
+ * @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',
+    'layout--threecol-25-50-25',
+  ]
+%}
+{% if content %}
+  <div{{ attributes.addClass(classes) }}>
+    {% if content.top %}
+      <div class="layout__region layout__region--top">
+        {{ content.top }}
+      </div>
+    {% endif %}
+
+    {% if content.first %}
+      <div class="layout__region layout__region--first">
+        {{ content.first }}
+      </div>
+    {% endif %}
+
+    {% if content.second %}
+      <div class="layout__region layout__region--second">
+        {{ content.second }}
+      </div>
+    {% endif %}
+
+    {% if content.third %}
+      <div class="layout__region layout__region--third">
+        {{ content.third }}
+      </div>
+    {% endif %}
+
+    {% if content.bottom %}
+      <div class="layout__region layout__region--bottom">
+        {{ 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..5eabb04
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--threecol-33-34-33.html.twig
@@ -0,0 +1,54 @@
+{#
+/**
+ * @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',
+    'layout--threecol-33-34-33',
+  ]
+%}
+{% if content %}
+  <div{{ attributes.addClass(classes) }}>
+    {% if content.top %}
+      <div class="layout__region layout__region--top">
+        {{ content.top }}
+      </div>
+    {% endif %}
+
+    {% if content.first %}
+      <div class="layout__region layout__region--first">
+        {{ content.first }}
+      </div>
+    {% endif %}
+
+    {% if content.second %}
+      <div class="layout__region layout__region--second">
+        {{ content.second }}
+      </div>
+    {% endif %}
+
+    {% if content.third %}
+      <div class="layout__region layout__region--third">
+        {{ content.third }}
+      </div>
+    {% endif %}
+
+    {% if content.bottom %}
+      <div class="layout__region layout__region--bottom">
+        {{ 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..1099577
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--twocol-bricks.html.twig
@@ -0,0 +1,66 @@
+{#
+/**
+ * @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',
+    'layout--twocol-bricks',
+  ]
+%}
+{% if content %}
+  <div{{ attributes.addClass(classes) }}>
+    {% if content.top %}
+      <div class="layout__region layout__region--top">
+        {{ content.top }}
+      </div>
+    {% endif %}
+
+    {% if content.first_above %}
+      <div class="layout__region layout__region--first-above">
+        {{ content.first_above }}
+      </div>
+    {% endif %}
+
+    {% if content.second_above %}
+      <div class="layout__region layout__region--second-above">
+        {{ content.second_above }}
+      </div>
+    {% endif %}
+
+    {% if content.middle %}
+      <div class="layout__region layout__region--middle">
+        {{ content.middle }}
+      </div>
+    {% endif %}
+
+    {% if content.first_below %}
+      <div class="layout__region layout__region--first-below">
+        {{ content.first_below }}
+      </div>
+    {% endif %}
+
+    {% if content.second_below %}
+      <div class="layout__region layout__region--second-below">
+        {{ content.second_below }}
+      </div>
+    {% endif %}
+
+    {% if content.bottom %}
+      <div class="layout__region layout__region--bottom">
+        {{ content.bottom }}
+      </div>
+    {% endif %}
+  </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..b416cbd
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout--twocol.html.twig
@@ -0,0 +1,45 @@
+{#
+/**
+ * @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',
+    'layout--twocol',
+  ]
+%}
+{% if content %}
+  <div{{ attributes.addClass(classes) }}>
+    {% if content.top %}
+      <div class="layout__region layout__region--top">
+        {{ content.top }}
+      </div>
+    {% endif %}
+
+    {% if content.first %}
+      <div class="layout__region layout__region--first">
+        {{ content.first }}
+      </div>
+    {% endif %}
+
+    {% if content.second %}
+      <div class="layout__region layout__region--second">
+        {{ content.second }}
+      </div>
+    {% endif %}
+
+    {% if content.bottom %}
+      <div class="layout__region layout__region--bottom">
+        {{ content.bottom }}
+      </div>
+    {% endif %}
+  </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..6ba96d5
--- /dev/null
+++ b/core/themes/stable/templates/layout/layout.html.twig
@@ -0,0 +1,23 @@
+{#
+/**
+ * @file
+ * Template for a generic layout.
+ */
+#}
+{%
+  set classes = [
+    'layout',
+    'layout--' ~ layout.id|clean_class,
+  ]
+%}
+{% if content %}
+  <div{{ attributes.addClass(classes) }}>
+    {% for region in layout.getRegionNames %}
+      {% if content[region] %}
+        <div class="{{ 'layout__region layout__region--' ~ region|clean_class }}">
+          {{ content[region] }}
+        </div>
+      {% endif %}
+    {% endfor %}
+  </div>
+{% endif %}