10
Just to make it more confusing

...
You could also assign the numerical value to a Smarty template variable, and then do the actual display within the template.
footer.php
le="color: #000000"><?php $xoopsLogger->stopTime(); $xoopsTpl->assign('ftime', $xoopsLogger->dumpTime());
in template
le="color: #000000"><?php Erstellungszeit der Seite = <{$ftime|string_format:"%.3f"}> sekunden.
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You could also use language strings for the text.
le="color: #000000"><?php <{$smarty.const._XXXX}> = <{$ftime|string_format:"%.3f"}> <{$smarty.const._YYYY}>.
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You might be able to make it work even with caching by using the Smarty
insert tag.