diff -r be944660c56a -r 3d72ae0968f4 wp/wp-admin/includes/class-walker-category-checklist.php
--- a/wp/wp-admin/includes/class-walker-category-checklist.php	Wed Sep 21 18:19:35 2022 +0200
+++ b/wp/wp-admin/includes/class-walker-category-checklist.php	Tue Sep 27 16:37:53 2022 +0200
@@ -61,14 +61,19 @@
 	 * @see Walker::start_el()
 	 *
 	 * @since 2.5.1
+	 * @since 5.9.0 Renamed `$category` to `$data_object` and `$id` to `$current_object_id`
+	 *              to match parent class for PHP 8 named parameter support.
 	 *
-	 * @param string  $output   Used to append additional content (passed by reference).
-	 * @param WP_Term $category The current term object.
-	 * @param int     $depth    Depth of the term in reference to parents. Default 0.
-	 * @param array   $args     An array of arguments. @see wp_terms_checklist()
-	 * @param int     $id       ID of the current term.
+	 * @param string  $output            Used to append additional content (passed by reference).
+	 * @param WP_Term $data_object       The current term object.
+	 * @param int     $depth             Depth of the term in reference to parents. Default 0.
+	 * @param array   $args              An array of arguments. @see wp_terms_checklist()
+	 * @param int     $current_object_id Optional. ID of the current term. Default 0.
 	 */
-	public function start_el( &$output, $category, $depth = 0, $args = array(), $id = 0 ) {
+	public function start_el( &$output, $data_object, $depth = 0, $args = array(), $current_object_id = 0 ) {
+		// Restores the more descriptive, specific name for use within this method.
+		$category = $data_object;
+
 		if ( empty( $args['taxonomy'] ) ) {
 			$taxonomy = 'category';
 		} else {
@@ -120,13 +125,14 @@
 	 * @see Walker::end_el()
 	 *
 	 * @since 2.5.1
+	 * @since 5.9.0 Renamed `$category` to `$data_object` to match parent class for PHP 8 named parameter support.
 	 *
-	 * @param string  $output   Used to append additional content (passed by reference).
-	 * @param WP_Term $category The current term object.
-	 * @param int     $depth    Depth of the term in reference to parents. Default 0.
-	 * @param array   $args     An array of arguments. @see wp_terms_checklist()
+	 * @param string  $output      Used to append additional content (passed by reference).
+	 * @param WP_Term $data_object The current term object.
+	 * @param int     $depth       Depth of the term in reference to parents. Default 0.
+	 * @param array   $args        An array of arguments. @see wp_terms_checklist()
 	 */
-	public function end_el( &$output, $category, $depth = 0, $args = array() ) {
+	public function end_el( &$output, $data_object, $depth = 0, $args = array() ) {
 		$output .= "</li>\n";
 	}
 }