add_users WordPress user capability
User capability “add_users” was added to the WordPress “Administrator” user role since WordPress version 3.0. But this capability is not used yet by WordPress itself in any form. Perhaps it was added for use in the future versions and could be use by themes and plugins developers of course. It does nothing in the WordPress 3.3.1. So you may skip it temporally in your WordPress capabilities system research.
The only place where you can find ‘add_users’ WordPress user capability in WordPress source code is
$role->add_cap( 'add_users' );
Tags: capability, user capability, User Role, WordPress