diff --git a/src/wp-includes/class-wp-admin-bar.php b/src/wp-includes/class-wp-admin-bar.php
index dc6ea0993c..43bdadccd6 100644
--- a/src/wp-includes/class-wp-admin-bar.php
+++ b/src/wp-includes/class-wp-admin-bar.php
@@ -19,21 +19,14 @@ class WP_Admin_Bar {
 	public $user;
 
 	/**
-	 * @since 3.3.0
+	 * Deprecated menu property.
 	 *
-	 * @param string $name
-	 * @return string|array|void
+	 * @since 3.1.0
+	 * @deprecated 3.3.0 Modify admin bar nodes with WP_Admin_Bar::get_node(),
+	 *                   WP_Admin_Bar::add_node(), and WP_Admin_Bar::remove_node().
+	 * @var array
 	 */
-	public function __get( $name ) {
-		switch ( $name ) {
-			case 'proto':
-				return is_ssl() ? 'https://' : 'http://';
-
-			case 'menu':
-				_deprecated_argument( 'WP_Admin_Bar', '3.3.0', 'Modify admin bar nodes with WP_Admin_Bar::get_node(), WP_Admin_Bar::add_node(), and WP_Admin_Bar::remove_node(), not the <code>menu</code> property.' );
-				return array(); // Sorry, folks.
-		}
-	}
+	public $menu = array();
 
 	/**
 	 * Initializes the admin bar.
diff --git a/tests/phpunit/tests/adminbar.php b/tests/phpunit/tests/adminbar.php
index cec80d0cae..aa8043e7ec 100644
--- a/tests/phpunit/tests/adminbar.php
+++ b/tests/phpunit/tests/adminbar.php
@@ -754,4 +754,33 @@ class Tests_AdminBar extends WP_UnitTestCase {
 			'network-admin-o'      => 'manage_network_options',
 		);
 	}
+
+	/**
+	 * This test ensures that WP_Admin_Bar::$proto is not defined (including magic methods).
+	 *
+	 * @ticket 56876
+	 * @coversNothing
+	 */
+	public function test_proto_property_is_not_defined() {
+		$admin_bar = new WP_Admin_Bar();
+		$this->assertFalse( property_exists( $admin_bar, 'proto' ), 'WP_Admin_Bar::$proto should not be defined.' );
+		$this->assertFalse( isset( $admin_bar->proto ), 'WP_Admin_Bar::$proto should not be defined.' );
+	}
+
+	/**
+	 * This test ensures that WP_Admin_Bar::$menu is declared as a "regular" class property.
+	 *
+	 * @ticket 56876
+	 * @coversNothing
+	 */
+	public function test_menu_property_is_defined() {
+		$admin_bar = new WP_Admin_Bar();
+		$this->assertTrue( property_exists( $admin_bar, 'menu' ), 'WP_Admin_Bar::$proto property should be defined.' );
+
+		$menu_property = new ReflectionProperty( WP_Admin_Bar::class, 'menu' );
+		$this->assertTrue( $menu_property->isPublic(), 'WP_Admin_Bar::$menu should be public.' );
+
+		$this->assertTrue( isset( $admin_bar->menu ), 'WP_Admin_Bar::$menu should be set.' );
+		$this->assertSame( array(), $admin_bar->menu, 'WP_Admin_Bar::$menu should be equal to an empty array.' );
+	}
 }