<p>Allows direct modification of the flat and tree versions of the navigation array after it has been rendered from the navigation cache.</p>

<p>Callback signature:</p>
<blockquote><code><em>\XF\Pub\App</em> $app, <em>array</em> &amp;$navigationFlat, <em>array</em> &amp;$navigationTree</code></blockquote>

<p>Arguments:</p>
<ol>
	<li><code><em>\XF\Pub\App</em> $app</code> - Public App object.</li>
	<li><code><em>array</em> &amp;$navigationFlat</code> - Flat array of navigation entries.</li>
	<li><code><em>array</em> &amp;$navigationTree</code> - Nested tree of navigation entries, grouped by their applicable parents.</li>
</ol>