What could it be?
Sony XDev is sort of like the technical arm of Sony’s European studios- a studio highly accomplished in technical work, helping out other studios where they need help, sort of like Sony Santa Monica in America, or Sony Japan in Japan. And it looks like they currently have their fingers in a lot of pies, because on their Twitter account, they teased numerous secret projects (as well as some not so secret projects) that they apparently are working on right now.
It is unclear if their work in this case is just technical assistance for other studios on their games, or if they are working on an original game of their own- hopefully it is the latter, and they get the chance to show off their own game design chops! Regardless of what it is, however, it is exciting to note that there is still some stuff upcoming for the PS4 that we don’t know about.
Hopefully, some of it is announced at E3 later this year.