diff -r 7b1b88e27a20 -r 48c4eec2b7e6 wp/wp-admin/includes/class-wp-ajax-upgrader-skin.php
--- a/wp/wp-admin/includes/class-wp-ajax-upgrader-skin.php	Thu Sep 29 08:06:27 2022 +0200
+++ b/wp/wp-admin/includes/class-wp-ajax-upgrader-skin.php	Fri Sep 05 18:40:08 2025 +0200
@@ -19,6 +19,27 @@
 class WP_Ajax_Upgrader_Skin extends Automatic_Upgrader_Skin {
 
 	/**
+	 * Plugin info.
+	 *
+	 * The Plugin_Upgrader::bulk_upgrade() method will fill this in
+	 * with info retrieved from the get_plugin_data() function.
+	 *
+	 * @var array Plugin data. Values will be empty if not supplied by the plugin.
+	 */
+	public $plugin_info = array();
+
+	/**
+	 * Theme info.
+	 *
+	 * The Theme_Upgrader::bulk_upgrade() method will fill this in
+	 * with info retrieved from the Theme_Upgrader::theme_info() method,
+	 * which in turn calls the wp_get_theme() function.
+	 *
+	 * @var WP_Theme|false The theme's info object, or false.
+	 */
+	public $theme_info = false;
+
+	/**
 	 * Holds the WP_Error object.
 	 *
 	 * @since 4.6.0
@@ -97,7 +118,7 @@
 				$string = $this->upgrader->strings[ $string ];
 			}
 
-			if ( false !== strpos( $string, '%' ) ) {
+			if ( str_contains( $string, '%' ) ) {
 				if ( ! empty( $args ) ) {
 					$string = vsprintf( $string, $args );
 				}