Nintendo Treehouse is a product development division at Nintendo of America. While its main purpose is translating the games for the Americas into English, French and Spanish, they also help with QA Testing and product management. Starting in 2014, Nintendo Treehouse did a few livestreams including ones for the entirety of E3 2014 and the shows after.
However, they are prone to fill their localizations with outdated memes.
https://nintendotreehouse.tumblr.com/ < Link to Treehouse development blog