er <span>&#45;&gt;</span> <a href="index.html#type-t">t</a> <span>&#45;&gt;</span> unit</code></dt></dl></details></div></div></div></details></div></div></div><dl><dt class="spec value" id="val-describe"><a href="#val-describe" class="anchor"></a><code><span class="keyword">val</span> describe : Stdlib.Format.formatter <span>&#45;&gt;</span> <a href="index.html#type-t">t</a> <span>&#45;&gt;</span> unit</code></dt><dd><p>Pretty printer used for trace construction; <code>pp</code> is used for debug output.</