core-bundle/src/Resources/contao/classes/FrontendTemplate.php
public static function addToUrl($strRequest, $blnIgnoreParams=false, $arrUnset=array())
	{
		return Frontend::addToUrl($strRequest, $blnIgnoreParams, $arrUnset);
	}
public static function addToUrl($strRequest, $blnIgnoreParams=false, $arrUnset=array())
	{
		return Frontend::addToUrl($strRequest, $blnIgnoreParams, $arrUnset);
	}
Point to `Frontend::addToUrl()` in front end templates (see #6736)

@param string  $strRequest      The request string to be added
@param boolean $blnIgnoreParams If true, the $_GET parameters will be ignored
@param array   $arrUnset        An optional array of keys to unset

@return string The new URI string