Source

File: wp-includes/class-wp-customize-section.php

protected function render_template() {
		?>
		<li id="accordion-section-{{ data.id }}" class="accordion-section control-section control-section-{{ data.type }}">
			<h3 class="accordion-section-title" tabindex="0">
				{{ data.title }}
				<span class="screen-reader-text"><?php _e( 'Press return or enter to open this section' ); ?></span>
			</h3>
			<ul class="accordion-section-content">
				<li class="customize-section-description-container section-meta <# if ( data.description_hidden ) { #>customize-info<# } #>">
					<div class="customize-section-title">
						<button class="customize-section-back" tabindex="-1">
							<span class="screen-reader-text"><?php _e( 'Back' ); ?></span>
						</button>
						<h3>
							<span class="customize-action">
								{{{ data.customizeAction }}}
							</span>
							{{ data.title }}
						</h3>
						<# if ( data.description && data.description_hidden ) { #>
							<button type="button" class="customize-help-toggle dashicons dashicons-editor-help" aria-expanded="false"><span class="screen-reader-text"><?php _e( 'Help' ); ?></span></button>
							<div class="description customize-section-description">
								{{{ data.description }}}
							</div>
						<# } #>

						<div class="customize-control-notifications-container"></div>
					</div>

					<# if ( data.description && ! data.description_hidden ) { #>
						<div class="description customize-section-description">
							{{{ data.description }}}
						</div>
					<# } #>
				</li>
			</ul>
		</li>
		<?php
	}