If you open styles/prosilver/template/viewtopic_body.html you'll find this at the top.

HTML
<!-- IF S_FORUM_RULES -->
	<div class="rules<!-- IF U_FORUM_RULES --> rules-link<!-- ENDIF -->">
		<div class="inner">

		<!-- IF U_FORUM_RULES -->
			<a href="{U_FORUM_RULES}">{L_FORUM_RULES}</a>
		<!-- ELSE -->
			<strong>{L_FORUM_RULES}</strong><br />
			{FORUM_RULES}
		<!-- ENDIF -->

		</div>
	</div>
<!-- ENDIF -->