diff --git a/core/lib/Drupal/Core/Layout/Annotation/Layout.php b/core/lib/Drupal/Core/Layout/Annotation/Layout.php
index d2072c2..725aa43 100644
--- a/core/lib/Drupal/Core/Layout/Annotation/Layout.php
+++ b/core/lib/Drupal/Core/Layout/Annotation/Layout.php
@@ -112,6 +112,13 @@ class Layout extends Plugin {
   public $icon;
 
   /**
+   * The icon map.
+   *
+   * @var array optional
+   */
+  public $icon_map;
+
+  /**
    * An associative array of regions in this layout.
    *
    * The key of the array is the machine name of the region, and the value is
diff --git a/core/lib/Drupal/Core/Layout/LayoutDefinition.php b/core/lib/Drupal/Core/Layout/LayoutDefinition.php
index a2be60b..cc452a7 100644
--- a/core/lib/Drupal/Core/Layout/LayoutDefinition.php
+++ b/core/lib/Drupal/Core/Layout/LayoutDefinition.php
@@ -86,6 +86,15 @@ class LayoutDefinition extends PluginDefinition implements PluginDefinitionInter
   protected $icon;
 
   /**
+   * An array defining the regions of a layout.
+   *
+   * @var array|null
+   *
+   * @see \Drupal\Core\Layout\IconGeneratorInterface::generateSvgFromIconMap()
+   */
+  protected $icon_map;
+
+  /**
    * An associative array of regions in this layout.
    *
    * The key of the array is the machine name of the region, and the value is
@@ -372,6 +381,31 @@ public function setIconPath($icon) {
   }
 
   /**
+   * Gets the icon map for this layout definition.
+   *
+   * This should not be used if an icon path is specified. See ::getIcon().
+   *
+   * @return array|null
+   *   The icon map, if it exists.
+   */
+  public function getIconMap() {
+    return $this->icon_map;
+  }
+
+  /**
+   * Sets the icon map for this layout definition.
+   *
+   * @param array|null $icon_map
+   *   The icon map.
+   *
+   * @return $this
+   */
+  public function setIconMap($icon_map) {
+    $this->icon_map = $icon_map;
+    return $this;
+  }
+
+  /**
    * Builds a render array for an icon representing the layout.
    *
    * @param int $width
@@ -404,7 +438,7 @@ public function getIcon($width = 250, $height = 300, $stroke_width = 2, $padding
         '#height' => $height,
       ];
     }
-    elseif ($icon_map = $this->get('icon_map')) {
+    elseif ($icon_map = $this->getIconMap()) {
       $icon = $this->getIconGenerator()->generateSvgFromIconMap($icon_map, $width, $height, $stroke_width, $padding, $fill, $stroke);
     }
     return $icon;