diff --git a/wp-admin/includes/post.php b/wp-admin/includes/post.php
index f79c95428d..c13f2f7592 100644
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -2232,6 +2232,7 @@ function get_block_editor_server_block_settings() {
 		'styles'           => 'styles',
 		'textdomain'       => 'textdomain',
 		'parent'           => 'parent',
+		'ancestor'         => 'ancestor',
 		'keywords'         => 'keywords',
 		'example'          => 'example',
 		'variations'       => 'variations',
diff --git a/wp-includes/class-wp-block-type.php b/wp-includes/class-wp-block-type.php
index b3700e8d2e..47e6619fe2 100644
--- a/wp-includes/class-wp-block-type.php
+++ b/wp-includes/class-wp-block-type.php
@@ -58,6 +58,15 @@ class WP_Block_Type {
 	 */
 	public $parent = null;
 
+	/**
+	 * Setting ancestor makes a block available only inside the specified
+	 * block types at any position of the ancestor's block subtree.
+	 *
+	 * @since 6.0.0
+	 * @var array|null
+	 */
+	public $ancestor = null;
+
 	/**
 	 * Block type icon.
 	 *
@@ -207,6 +216,7 @@ class WP_Block_Type {
 	 * @since 5.6.0 Added the `api_version` property.
 	 * @since 5.8.0 Added the `variations` property.
 	 * @since 5.9.0 Added the `view_script` property.
+	 * @since 6.0.0 Added the `ancestor` property.
 	 *
 	 * @see register_block_type()
 	 *
@@ -221,6 +231,8 @@ class WP_Block_Type {
 	 *                                           search interfaces to arrange block types by category.
 	 *     @type array|null    $parent           Setting parent lets a block require that it is only
 	 *                                           available when nested within the specified blocks.
+	 *     @type array|null    $ancestor         Setting ancestor makes a block available only inside the specified
+	 *                                           block types at any position of the ancestor's block subtree.
 	 *     @type string|null   $icon             Block type icon.
 	 *     @type string        $description      A detailed block type description.
 	 *     @type string[]      $keywords         Additional keywords to produce block type as
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php
index c546a3082a..95b12e388a 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php
@@ -266,6 +266,7 @@ class WP_REST_Block_Types_Controller extends WP_REST_Controller {
 			'category',
 			'keywords',
 			'parent',
+			'ancestor',
 			'provides_context',
 			'uses_context',
 			'supports',
@@ -645,6 +646,16 @@ class WP_REST_Block_Types_Controller extends WP_REST_Controller {
 					'context'     => array( 'embed', 'view', 'edit' ),
 					'readonly'    => true,
 				),
+				'ancestor'           => array(
+					'description' => __( 'Ancestor blocks.' ),
+					'type'        => array( 'array', 'null' ),
+					'items'       => array(
+						'type' => 'string',
+					),
+					'default'     => null,
+					'context'     => array( 'embed', 'view', 'edit' ),
+					'readonly'    => true,
+				),
 				'keywords'         => $keywords_definition,
 				'example'          => $example_definition,
 			),
diff --git a/wp-includes/version.php b/wp-includes/version.php
index e8b3140256..77b88bc9ae 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.0-alpha-53083';
+$wp_version = '6.0-alpha-53084';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.