/usr/share/php/HTMLPurifier/HTMLModule/NonXMLCommonAttributes.php is in php-htmlpurifier 4.6.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20  | <?php
class HTMLPurifier_HTMLModule_NonXMLCommonAttributes extends HTMLPurifier_HTMLModule
{
    /**
     * @type string
     */
    public $name = 'NonXMLCommonAttributes';
    /**
     * @type array
     */
    public $attr_collections = array(
        'Lang' => array(
            'lang' => 'LanguageCode',
        )
    );
}
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