silverstripe-framework/admin/templates/Includes/BackLink_Button.ss

<% if $Backlink %>
	<div class="cms_backlink">
		<a class="backlink ss-ui-button cms-panel-link" data-icon="back" href="$Backlink">
			<% _t('BackLink_Button.ss.Back', 'Back') %>
		</a>
	</div>
<% end_if %>