diff -r be944660c56a -r 3d72ae0968f4 wp/wp-includes/class-wp-post-type.php
--- a/wp/wp-includes/class-wp-post-type.php	Wed Sep 21 18:19:35 2022 +0200
+++ b/wp/wp-includes/class-wp-post-type.php	Tue Sep 27 16:37:53 2022 +0200
@@ -45,6 +45,14 @@
 	public $labels;
 
 	/**
+	 * Default labels.
+	 *
+	 * @since 6.0.0
+	 * @var (string|null)[][] $default_labels
+	 */
+	protected static $default_labels = array();
+
+	/**
 	 * A short descriptive summary of what the post type is.
 	 *
 	 * Default empty.
@@ -92,6 +100,7 @@
 	 * Whether queries can be performed on the front end for the post type as part of `parse_request()`.
 	 *
 	 * Endpoints would include:
+	 *
 	 * - `?post_type={post_type_key}`
 	 * - `?{post_type_key}={single_post_slug}`
 	 * - `?{post_type_query_var}={single_post_slug}`
@@ -117,8 +126,8 @@
 	 * Where to show the post type in the admin menu.
 	 *
 	 * To work, $show_ui must be true. If true, the post type is shown in its own top level menu. If false, no menu is
-	 * shown. If a string of an existing top level menu (eg. 'tools.php' or 'edit.php?post_type=page'), the post type
-	 * will be placed as a sub-menu of that.
+	 * shown. If a string of an existing top level menu ('tools.php' or 'edit.php?post_type=page', for example), the
+	 * post type will be placed as a sub-menu of that.
 	 *
 	 * Default is the value of $show_ui.
 	 *
@@ -359,6 +368,14 @@
 	public $rest_base;
 
 	/**
+	 * The namespace for this post type's REST API endpoints.
+	 *
+	 * @since 5.9.0
+	 * @var string|bool $rest_namespace
+	 */
+	public $rest_namespace;
+
+	/**
 	 * The controller for this post type's REST API endpoints.
 	 *
 	 * Custom controllers must extend WP_REST_Controller.
@@ -423,6 +440,26 @@
 		 */
 		$args = apply_filters( 'register_post_type_args', $args, $this->name );
 
+		$post_type = $this->name;
+
+		/**
+		 * Filters the arguments for registering a specific post type.
+		 *
+		 * The dynamic portion of the filter name, `$post_type`, refers to the post type key.
+		 *
+		 * Possible hook names include:
+		 *
+		 *  - `register_post_post_type_args`
+		 *  - `register_page_post_type_args`
+		 *
+		 * @since 6.0.0
+		 *
+		 * @param array  $args      Array of arguments for registering a post type.
+		 *                          See the register_post_type() function for accepted arguments.
+		 * @param string $post_type Post type key.
+		 */
+		$args = apply_filters( "register_{$post_type}_post_type_args", $args, $this->name );
+
 		$has_edit_link = ! empty( $args['_edit_link'] );
 
 		// Args prefixed with an underscore are reserved for internal use.
@@ -452,6 +489,7 @@
 			'delete_with_user'      => null,
 			'show_in_rest'          => false,
 			'rest_base'             => false,
+			'rest_namespace'        => false,
 			'rest_controller_class' => false,
 			'template'              => array(),
 			'template_lock'         => false,
@@ -473,6 +511,11 @@
 			$args['show_ui'] = $args['public'];
 		}
 
+		// If not set, default rest_namespace to wp/v2 if show_in_rest is true.
+		if ( false === $args['rest_namespace'] && ! empty( $args['show_in_rest'] ) ) {
+			$args['rest_namespace'] = 'wp/v2';
+		}
+
 		// If not set, default to the setting for 'show_ui'.
 		if ( null === $args['show_in_menu'] || ! $args['show_ui'] ) {
 			$args['show_in_menu'] = $args['show_ui'];
@@ -770,4 +813,69 @@
 
 		return $this->rest_controller;
 	}
+
+	/**
+	 * Returns the default labels for post types.
+	 *
+	 * @since 6.0.0
+	 *
+	 * @return (string|null)[][] The default labels for post types.
+	 */
+	public static function get_default_labels() {
+		if ( ! empty( self::$default_labels ) ) {
+			return self::$default_labels;
+		}
+
+		self::$default_labels = array(
+			'name'                     => array( _x( 'Posts', 'post type general name' ), _x( 'Pages', 'post type general name' ) ),
+			'singular_name'            => array( _x( 'Post', 'post type singular name' ), _x( 'Page', 'post type singular name' ) ),
+			'add_new'                  => array( _x( 'Add New', 'post' ), _x( 'Add New', 'page' ) ),
+			'add_new_item'             => array( __( 'Add New Post' ), __( 'Add New Page' ) ),
+			'edit_item'                => array( __( 'Edit Post' ), __( 'Edit Page' ) ),
+			'new_item'                 => array( __( 'New Post' ), __( 'New Page' ) ),
+			'view_item'                => array( __( 'View Post' ), __( 'View Page' ) ),
+			'view_items'               => array( __( 'View Posts' ), __( 'View Pages' ) ),
+			'search_items'             => array( __( 'Search Posts' ), __( 'Search Pages' ) ),
+			'not_found'                => array( __( 'No posts found.' ), __( 'No pages found.' ) ),
+			'not_found_in_trash'       => array( __( 'No posts found in Trash.' ), __( 'No pages found in Trash.' ) ),
+			'parent_item_colon'        => array( null, __( 'Parent Page:' ) ),
+			'all_items'                => array( __( 'All Posts' ), __( 'All Pages' ) ),
+			'archives'                 => array( __( 'Post Archives' ), __( 'Page Archives' ) ),
+			'attributes'               => array( __( 'Post Attributes' ), __( 'Page Attributes' ) ),
+			'insert_into_item'         => array( __( 'Insert into post' ), __( 'Insert into page' ) ),
+			'uploaded_to_this_item'    => array( __( 'Uploaded to this post' ), __( 'Uploaded to this page' ) ),
+			'featured_image'           => array( _x( 'Featured image', 'post' ), _x( 'Featured image', 'page' ) ),
+			'set_featured_image'       => array( _x( 'Set featured image', 'post' ), _x( 'Set featured image', 'page' ) ),
+			'remove_featured_image'    => array( _x( 'Remove featured image', 'post' ), _x( 'Remove featured image', 'page' ) ),
+			'use_featured_image'       => array( _x( 'Use as featured image', 'post' ), _x( 'Use as featured image', 'page' ) ),
+			'filter_items_list'        => array( __( 'Filter posts list' ), __( 'Filter pages list' ) ),
+			'filter_by_date'           => array( __( 'Filter by date' ), __( 'Filter by date' ) ),
+			'items_list_navigation'    => array( __( 'Posts list navigation' ), __( 'Pages list navigation' ) ),
+			'items_list'               => array( __( 'Posts list' ), __( 'Pages list' ) ),
+			'item_published'           => array( __( 'Post published.' ), __( 'Page published.' ) ),
+			'item_published_privately' => array( __( 'Post published privately.' ), __( 'Page published privately.' ) ),
+			'item_reverted_to_draft'   => array( __( 'Post reverted to draft.' ), __( 'Page reverted to draft.' ) ),
+			'item_scheduled'           => array( __( 'Post scheduled.' ), __( 'Page scheduled.' ) ),
+			'item_updated'             => array( __( 'Post updated.' ), __( 'Page updated.' ) ),
+			'item_link'                => array(
+				_x( 'Post Link', 'navigation link block title' ),
+				_x( 'Page Link', 'navigation link block title' ),
+			),
+			'item_link_description'    => array(
+				_x( 'A link to a post.', 'navigation link block description' ),
+				_x( 'A link to a page.', 'navigation link block description' ),
+			),
+		);
+
+		return self::$default_labels;
+	}
+
+	/**
+	 * Resets the cache for the default labels.
+	 *
+	 * @since 6.0.0
+	 */
+	public static function reset_default_labels() {
+		self::$default_labels = array();
+	}
 }