$GLOBALS[‘TYPO3_USER_SETTINGS’]

New array is similar to TCA in structure, but applies to BE user settings. It can be manipulated just like TCA, but has fewer options and properties. From Core API documentation:
$GLOBALS[‘TYPO3_USER_SETTINGS’][‘ctrl’]
property: dividers2tabs
data type: int
description: Render user setup with(out) tabs, settings are as in TCA: 0 = no tabs, 1 = tabs, empty tabs are hidden, 2 = tabs, empty tabs are disabled
default: 1

$GLOBALS[‘TYPO3_USER_SETTINGS’][‘columns’][fieldname]
This contains the configuration array for single fields in the user settings. This array allows the following configurations:

property: type
data type: string
description: defines the type of the input field
allowed: text, password, check, select, user

A field with type=user also need a userFunc defined.
Example:

'fieldname' => array(
'type' => 'user',
'label' => 'the label',
'userFunc' => 'classname->theRenderFunction',
)

property: label
data type: string
description: label for the input field

property: csh
data type: string
description: CSH key for the input field

property: access
data type: string
description: access control. At the moment only a admin-check is implemented
allowed: admin

property: table
data type: string
description: if the user setting is saved in a DB table, this property sets the table. At the moment only be_users is implemented
allowed: be_users

property: eval
data type: string
description: eval field to md5 (used for password field)
allowed: md5

property: items
data type: array
description: array of key-value pair for select items
allowed: only used by type=select

property: itemsProcFunc
data type: string
description: define external method for render items of select. Other than TCA you have to render the
<select> tag too
allowed: only for type=select, use class->method syntax

$GLOBALS[‘TYPO3_USER_SETTINGS’][‘showitem’]
This string is used for rendering the FORM in the user setup module. Fields are rendered in the order of this string containing the commalist of fieldnames.
To use a tab insert a “–div–;LABEL” item in the commalist.

More info:
RFC: #11019: User Setup Rewrite #4
http://bugs.typo3.org/view.php?id=11019
RFC: #11407: [Feature] Allow type=”user” in user setup
http://bugs.typo3.org/view.php?id=11407