header.php

<div class="toggle-wrapper search-toggle-wrapper">

								<button class="toggle search-toggle desktop-search-toggle" data-toggle-target=".search-modal" data-toggle-body-class="showing-search-modal" data-set-focus=".search-modal .search-field" aria-expanded="false">
									<span class="toggle-inner">
										<?php twentytwenty_the_theme_svg( 'search' ); ?>
										<span class="toggle-text"><?php _e( 'Search', 'twentytwenty' ); ?></span>
									</span>
								</button><!-- .search-toggle -->

							</div>

代码：

twentytwenty_the_theme_svg( 'search' )

对应html

<span class="toggle-icon">
<svg class="svg-icon" aria-hidden="true" role="img" focusable="false" xmlns="http://www.w3.org/2000/svg" width="23" height="23" viewBox="0 0 23 23"><path d="M38.710696,48.0601792 L43,52.3494831 L41.3494831,54 L37.0601792,49.710696 C35.2632422,51.1481185 32.9839107,52.0076499 30.5038249,52.0076499 C24.7027226,52.0076499 20,47.3049272 20,41.5038249 C20,35.7027226 24.7027226,31 30.5038249,31 C36.3049272,31 41.0076499,35.7027226 41.0076499,41.5038249 C41.0076499,43.9839107 40.1481185,46.2632422 38.710696,48.0601792 Z M36.3875844,47.1716785 C37.8030221,45.7026647 38.6734666,43.7048964 38.6734666,41.5038249 C38.6734666,36.9918565 35.0157934,33.3341833 30.5038249,33.3341833 C25.9918565,33.3341833 22.3341833,36.9918565 22.3341833,41.5038249 C22.3341833,46.0157934 25.9918565,49.6734666 30.5038249,49.6734666 C32.7048964,49.6734666 34.7026647,48.8030221 36.1716785,47.3875844 C36.2023931,47.347638 36.2360451,47.3092237 36.2726343,47.2726343 C36.3092237,47.2360451 36.347638,47.2023931 36.3875844,47.1716785 Z" transform="translate(-20 -31)" /></svg>								</span>