/usr/share/php/xajax/xajax_core/ is in php-xajax 0.5-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/xajax/xajax_core/legacy.inc.php
/usr/share/php/xajax/xajax_core/plugin_layer/
/usr/share/php/xajax/xajax_core/plugin_layer/support/
/usr/share/php/xajax/xajax_core/plugin_layer/support/xajaxCallableObject.inc.php
/usr/share/php/xajax/xajax_core/plugin_layer/support/xajaxEvent.inc.php
/usr/share/php/xajax/xajax_core/plugin_layer/support/xajaxUserFunction.inc.php
/usr/share/php/xajax/xajax_core/plugin_layer/xajaxCallableObjectPlugin.inc.php
/usr/share/php/xajax/xajax_core/plugin_layer/xajaxDefaultIncludePlugin.inc.php
/usr/share/php/xajax/xajax_core/plugin_layer/xajaxEventPlugin.inc.php
/usr/share/php/xajax/xajax_core/plugin_layer/xajaxFunctionPlugin.inc.php
/usr/share/php/xajax/xajax_core/plugin_layer/xajaxScriptPlugin.inc.php
/usr/share/php/xajax/xajax_core/xajax.inc.php
/usr/share/php/xajax/xajax_core/xajaxArgumentManager.inc.php
/usr/share/php/xajax/xajax_core/xajaxCall.inc.php
/usr/share/php/xajax/xajax_core/xajaxCompress.inc.php
/usr/share/php/xajax/xajax_core/xajaxControl.inc.php
/usr/share/php/xajax/xajax_core/xajaxLanguageManager.inc.php
/usr/share/php/xajax/xajax_core/xajaxPlugin.inc.php
/usr/share/php/xajax/xajax_core/xajaxPluginManager.inc.php
/usr/share/php/xajax/xajax_core/xajaxRequest.inc.php
/usr/share/php/xajax/xajax_core/xajaxResponse.inc.php
/usr/share/php/xajax/xajax_core/xajaxResponseManager.inc.php
/usr/share/php/xajax/xajax_core/xajax_lang_de.inc.php
/usr/share/php/xajax/xajax_core/xajax_lang_nl.inc.php