code/Debug/Block/Abstract.php
public function formatNumber($number, $precision = 2)
    {
        return $this->helper->useStoreLocale() ? $this->helper->formatNumber($number, $precision) : number_format($number, $precision);
    }
public function formatNumber($number, $precision = 2)
    {
        return $this->helper->useStoreLocale() ? $this->helper->formatNumber($number, $precision) : number_format($number, $precision);
    }
Returns number formatted based on current locale

@param mixed $number
@param int   $precision
@return string