This is a combination of the Off-Canvas and Responsive Top Bar menus. On small screens, an off-canvas menu will be used; on medium and larger screens, the responsive navigation patterns will be utilized. To use this menu type, change the template part in header.php to:
<?php get_template_part( 'parts/nav', 'offcanvas-topbar' ); ?>
Off-Canvas Top Bar Settings
By default, an off-canvas menu will be triggered on small screens. This can be adjusted in the parts/nav-offcanvas-topbar.php file.