WordPress/wp-includes/capabilities.php

<?php
/**
 * Core User Role & Capabilities API
 *
 * @package WordPress
 * @subpackage Users
 * @since 2.0.0
 */

/** WP_Roles class */
require_once( ABSPATH . WPINC . '/class-wp-roles.php' );

/** WP_Role class */
require_once( ABSPATH . WPINC . '/class-wp-role.php' );

/** WP_User class */
require_once( ABSPATH . WPINC . '/class-wp-user.php' );

/** Core capabilities functionality */
require_once( ABSPATH . WPINC . '/capabilities-functions.php' );