twentynineteen_add_ellipses_to_nav( string $nav_menu, object $args ): string

132function twentynineteen_add_ellipses_to_nav( $nav_menu, $args ) {133 134	if ( 'menu-1' === $args->theme_location ) :135 136		$nav_menu .= '137			<div class="main-menu-more">138				<ul class="main-menu">139					<li class="menu-item menu-item-has-children">140						<button class="submenu-expand main-menu-more-toggle is-empty" tabindex="-1"141							aria-label="' . esc_attr__( 'More', 'twentynineteen' ) . '" aria-haspopup="true" aria-expanded="false">' .142							twentynineteen_get_icon_svg( 'arrow_drop_down_ellipsis' ) . '143						</button>144						<ul class="sub-menu hidden-links">145							<li class="mobile-parent-nav-menu-item">146								<button class="menu-item-link-return">' .147									twentynineteen_get_icon_svg( 'chevron_left' ) .148									esc_html__( 'Back', 'twentynineteen' ) . '149								</button>150							</li>151						</ul>152					</li>153				</ul>154			</div>';155 156	endif;157 158	return $nav_menu;159}