pod2html reports errors by including something akin to the following in the output:

<h1 id="POD-ERRORS">POD ERRORS</h1>

<p>Hey! <b>The above document had some coding errors, which are explai
+ned below:</b></p>

<dl>

<dt id="Around-line-16">Around line 16:</dt>
<dd>

<p>Unterminated C&lt;...&gt; sequence</p>
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MetaCPAN's handler for the pod2html web tool parses the generated output to extract this. Another possibility is a that this goes awry.