TYPO3 Core

I agree that it needs to be changed, but I don't know if it's a good idea if the URL is just removed. Suggestion: "$code ($testString)"

What do you think?

In my opinion the return of $code at the end of the function does not remove the Url, because there are two returns already if an Url is found. So the return of $code is only done if no link or mail is found.
I have c&p the changed method as example:

function linkUrlMail($code,$testString)    {

// Check for URL:
        $schema = parse_url($testString);
        if ($schema['scheme'] && t3lib_div::inList('http,https,ftp',$schema['scheme']))    {
            return '<a href="'.htmlspecialchars($testString).'" target="_blank">'.$code.'</a>';
        }

// check for email:
        if (t3lib_div::validEmail($testString))    {
            return '<a href="mailto:'.htmlspecialchars($testString).'" target="_blank">'.$code.'</a>';
        }

// Return if nothing else...
        return $code;
        // instead of return $testString;
    }