MW has wrapper functions for querystring building etc
It saves having to do stuff like
$delimiter = ( strpos( $mobileViewUrl, "?" ) !== false ) ? "&" : "?";
And also makes sure that all parameters are properly encoded
As per a request on #wikimedia-tech where this was giving validation errors
<li id="mobileview"><a href='/w/index.php?title=Datei%3ALogo_African_Pygmy_Goat.png&action=edit&useFormat=mobile'>Mobile View</a></li>
r93561
Version: unspecified
Severity: normal