How to run the php inside an XML file?

I’ve been tasked with editing the PHP inside an XML file. I had no idea this was a thing people did, and I wish they didn’t, because I don’t understand it. So I tried to look it up and I came across this question and answer about how to add php to an XML file.

It seemed like a really promising QA, because the format suggested by the top answer (using “<![CDATA[” and “]]>” around the PHP is exactly what’s happening in the xml file I’ve been tasked to edit.

But now my question is… How the heck do I run the thing? It obviously can’t run just by doing php -S localhost:8000, because it’s not php. there is no <?php or ?>, so the interpreter wouldn’t know what was php and what wasn’t.

Why is there php in the xml file? and what do now that it’s already happened?

Here’s a minimal example (not the actual file I’m working with).

<?xml version="1.0" encoding="ISO-8859-1"?>
<product productid="blah blah blah" active="1">
    <title>blah blah</title>
    <description><![CDATA[yadda yadda]]></description>
    <version>1.3</version>
    <url><![CDATA[http://www.foobar.com/mods/misc.php?do=producthelp&pid=hashbaz]]></url>
    <versioncheckurl><![CDATA[http://www.foobar.com/mods/misc.php?do=productcheck&pid=hashbaz]]></versioncheckurl>
    <dependencies>
        <dependency dependencytype="vbulletin" minversion="3.5" maxversion="5.0.0" />
    </dependencies>
    <codes>
    </codes>
    <templates>
    </templates>
    <stylevardfns>
    </stylevardfns>
    <stylevars>
    </stylevars>
    <plugins>
        <plugin active="1" executionorder="5">
            <title>some plugin</title>
            <hookname>some hook name</hookname>
            <phpcode><![CDATA[ echo "and now we're doing php for some reason???" . $qux; ]]></phpcode>
        </plugin>
    </plugins>
</products>