WP_User::level_reduction()
Method: Chooses the maximum level the user has.
Source: wp-includes/class-wp-user.php:673
WP_User::__set()
Method: Magic method for setting custom user fields.
Source: wp-includes/class-wp-user.php:346
WP_User::update_user_level_from_caps()
Method: Updates the maximum user level for the user.
Source: wp-includes/class-wp-user.php:693