use global var

src/wp-includes/class-wp-script-modules.php

@@ -30,31 +30,6 @@ class WP_Script_Modules {
 	 */
 	private $enqueued_before_registered = array();
 
-	/**
-	 * Container for the main instance of the class.
-	 *
-	 * @since 6.5.0
-	 * @var WP_Script_Modules|null
-	 */
-	private static $instance = null;
-
-	/**
-	 * Utility method to retrieve the main instance of the class.
-	 *
-	 * The instance will be created if it does not exist yet.
-	 *
-	 * @since 6.5.0
-	 *
-	 * @return WP_Script_Modules The main instance.
-	 */
-	public static function get_instance(): WP_Script_Modules {
-		if ( null === self::$instance ) {
-			self::$instance = new self();
-		}
-
-		return self::$instance;
-	}
-
 	/**
 	 * Registers the script module if no script module with that script module
 	 * identifier has already been registered.

src/wp-includes/script-modules.php

@@ -14,12 +14,20 @@
  * This function provides access to the WP_Script_Modules instance, creating one
  * if it doesn't exist yet.
  *
+ * @global WP_Script_Modules $wp_script_modules
+ *
  * @since 6.5.0
  *
  * @return WP_Script_Modules The main WP_Script_Modules instance.
  */
 function wp_script_modules(): WP_Script_Modules {
-	return WP_Script_Modules::get_instance();
+	global $wp_script_modules;
+
+	if ( ! ( $wp_script_modules instanceof WP_Script_Modules ) ) {
+		$wp_script_modules = new WP_Script_Modules();
+	}
+
+	return $wp_script_modules;
 }
 
 /**