diff -r 7b1b88e27a20 -r 48c4eec2b7e6 wp/wp-includes/rest-api/endpoints/class-wp-rest-widgets-controller.php
--- a/wp/wp-includes/rest-api/endpoints/class-wp-rest-widgets-controller.php	Thu Sep 29 08:06:27 2022 +0200
+++ b/wp/wp-includes/rest-api/endpoints/class-wp-rest-widgets-controller.php	Fri Sep 05 18:40:08 2025 +0200
@@ -715,7 +715,7 @@
 
 				if ( ! empty( $widget_object->widget_options['show_instance_in_rest'] ) ) {
 					// Use new stdClass so that JSON result is {} and not [].
-					$prepared['instance']['raw'] = empty( $instance ) ? new stdClass : $instance;
+					$prepared['instance']['raw'] = empty( $instance ) ? new stdClass() : $instance;
 				}
 			}
 		}
@@ -726,7 +726,9 @@
 
 		$response = rest_ensure_response( $prepared );
 
-		$response->add_links( $this->prepare_links( $prepared ) );
+		if ( rest_is_field_included( '_links', $fields ) || rest_is_field_included( '_embedded', $fields ) ) {
+			$response->add_links( $this->prepare_links( $prepared ) );
+		}
 
 		/**
 		 * Filters the REST API response for a widget.
@@ -859,9 +861,9 @@
 					'type'        => 'string',
 					'context'     => array(),
 					'arg_options' => array(
-						'sanitize_callback' => static function( $string ) {
+						'sanitize_callback' => static function ( $form_data ) {
 							$array = array();
-							wp_parse_str( $string, $array );
+							wp_parse_str( $form_data, $array );
 							return $array;
 						},
 					),