In moodle 2.4 $PAGE->layout_options used in frontpage.php in layout folder under theme folder what it means
$hascustommenu = (empty($PAGE->layout_options['nocustommenu']) && !empty($custommenu));
This relates to the Page layout when the custom menu is required on the page. The 'option' relates to all the places where the custom menu is not required on a page. These options are set in the themes config.php under $TMEME->layouts.