For my blogpost http://websupporter.net/blog/de/starter-content-fuer-themes/

starter-content-add-widgets.php

<?php
add_action( 'after_setup_theme', 'theme_start_content' );
function theme_starter_content() {

	add_theme_support( 'starter-content', array(
		'widgets' => array(
			'sidebar-1' => array(
				'text_business_info',
				'search',
			),
		),
	) );
}