I've just translated a "Thank You" pack of messages for Fundraising and WP10. There's a link in Mr. Wales' thankgiving appeal to a landing page. I set 'be-tarask' instead of 'en' but the landing page still stays in English. So does Bulgarian Thank You page. I'm sure the landing page is translated into Belarusian (Taraškievica) as I did it myself. So, what's the problem? :)