cl_khr_gl_event and GL_ARB_cl_event?

This NVIDIA presentation from last year discusses the use of cl_khr_gl_event, but I can’t find this extension in the drivers. I tried on both a GeForce 750 Ti on Windows 8.1 and GeForce 1070 on Windows 10, both with reasonably up to date drivers, and it’s not there.

To my knowledge these extension is Quadro and GeForce Titan only. Are you using one of them?