What is this template for?
This template will add a top bar to select the language you want to read the article in. For this to work, articles in other languages must be named like the english one and adding (Deutsch) (Español) (Français) after the name.
How do I use it?
To include that template, add the following to the article you are editing:
Where pagename is the name of the article you are editing in English.
Look at the ACL_and_Groups page. It is using the template right now.