Tools for developing virtual reality games and applications: something like the iOS SDK was for mobile development, for VR development.
Designing 3D content for VR is different to designing for video games or animation: content that is simply window-dressing when played on a monitor can be a major focus in VR. This means developers will need tools to make lots of very similar 3D models quickly & painlessly, tools for reusing animations, and tools for making lots of very similar textures.
More obviously, there are a lot of new rules that come for designing for VR - the developer has to avoid things like a rapidly changing focus, motion sickness and large jumps in the user’s viewing angle. Develops also need to think about supporting head tracking and other non-traditional controllers (e.g. treadmills, motion tracking), as well as binaural sound. There doesn’t yet exist a toolkit to automate away these issues.