['columns'] Section 

Defines the type of the input field

If type == user, then you need to define your own renderType too. If selectable items shall be filled by your own function, then you can use type == select and itemsProcFunc.

Example:

'startModule' => [
   'type' => 'select',
   'itemsProcFunc' => 'TYPO3\\CMS\\Setup\\Controller\\SetupModuleController->renderStartModuleSelect',
   'label' => 'LLL:EXT:setup/mod/locallang.xlf:startModule',
],

Label for the input field, should be a pointer to a localized label using the LLL: syntax.

Text of the button for type=button fields. Should be a pointer to a localized label using the LLL: syntax.

Access control. At the moment only a admin-check is implemented

If the user setting is saved in a DB table, this property sets the table. At the moment only be_users is implemented.

List of items for type=select fields. This should be a simple associative array with key-value pairs.

Defines an external method for rendering items of select-type fields. Contrary to what is done with the TCA you have to render the <select> tag too. Only used by type=select.

Use the usual class->method syntax.

JavaScript event triggered on click.

If true, JavaScript confirmation dialog is displayed.

JavaScript event triggered on confirmation.

Confirmation message.