Here's the statement from Wind River:[1] "Wind River contributed the Rocket kernel to Zephyr who brings together industry leaders in software and hardware to build an RTOS for IoT." There will still be a proprietary version of Rocket, which is the same kernel but also has components for connecting to Wind River's "App Cloud", which seems to be a hosted IDE. The Zephyr project offers only command line build tools under Linux.

[1] http://blogs.windriver.com/wind_river_blog/2016/02/wind-rive...