It's been available since last month, but browser-maker Opera has only today confirmed that it's Opera Devices Software Development Kit is providing the backend for the Boxee TV's HTML5 apps. Those already include the likes of YouTube, Spotify and Vimeo, but Opera says one of the big advantages of Boxee using the SDK is that future apps built with it will be able to be easily ported to the Boxee TV -- no word on any big additions just yet, though. Boxee's COO Tom Sella also notes that using the SDK "enabled us to add a lot of apps to Boxee TV without a lot of effort on our part." If tha