You can use this event for logging changes to user data, to enforce password security or to prevent unsuitable user names. It is signaled from method triggerUserMod in inc/auth/basic.class.php. This method should be called when modifying user data instead of calling createUser, modifyUser or deleteUsers directly.

• $data['type'] - Type of data modification (create, modify, delete)
• $data['params'] - Parameter array for the createUser, modifyUser or deleteUsers methods of an auth class.

Example:

Array (
    [type] => create
    [params] => Array
        (
            [0] => login
            [1] => password
            [2] => real name
            [3] => mail@example.com
            [4] => Array
                (
                    [0] => user
                    [1] => groups
                )

        )
    [modification_result] => password
)

what is modification_result?

The following plugins are known to handle this event and their source code may be a good start for understanding and implementing a handler yourself.

• Action Plugins
• Events
• Authentication Backends