htmlpurifier/library/HTMLPurifier/AttrTransform/Name.php

<?php

/**
 * Pre-transform that changes deprecated name attribute to ID if necessary
 */
class HTMLPurifier_AttrTransform_Name extends HTMLPurifier_AttrTransform
{

    public function transform($attr, $config, $context) {
        if (!isset($attr['name'])) return $attr;
        $id = $this->confiscateAttr($attr, 'name');
        if ( isset($attr['id']))   return $attr;
        $attr['id'] = $id;
        return $attr;
    }

}