Ticket #54931: 54391.patch

src/wp-includes/block-template-utils.php

@@ -791 +791 @@
                 $template = _build_block_template_result_from_post( $posts[0] );
 
                 if ( ! is_wp_error( $template ) ) {
-                        return $template;
+                        /** This filter is documented in wp-includes/block-template-utils.php */
+                        return apply_filters( 'get_block_template', $template, $id, $template_type );
                 }
         }