menu_options_$type and menu_parent_$type variables from menu.module are now third-party settings

The mentioned variables are now third-party settings of the node type configuration entity:

7.x

$menu_options = variable_get('menu_options_' . $type->type, array('main-menu'))
$menu_parent = variable_get('menu_parent_' . $type->type, 'main-menu:0')

8.x

$menu_options = $type->getThirdPartySetting('menu_ui', 'available_menus', array('main'));
$menu_parent = $type->getThirdPartySetting('menu_ui', 'parent', 'main:');

See also Modules can now store settings for node types using the new ThirdPartySettingsInterface