Intel Open-Source Technology Center developers have been working on Kabylake support in the open for the past few months now. This successor to Skylake is due out later this year and on the kernel-side there's a lot of Kabylake stuff for Linux 4.5.
With the kernel side progressing, Intel developers have now added the necessary PCI IDs and other information to their Mesa DRI driver and the DRM library (libdrm). The commits are now mainline as of this evening here and here.
Listed PCI IDs for the low-end Kabylake GT1 graphics are 0x5902, 0x5906, 0x590A, 0x590B, and 0x590E. Listed as "GT1.5" are 0x5913, 0x5915, and 0x5917. Marked as Kabylake GT2 are 0x5912, 0x5916, 0x591A, 0x591B, 0x591D, and 0x591E. There's also a "GT2F" part with a PCI ID of 0x5921. The Kabylake GT3 PCI IDs are 0x5926, 0x592A, and 0x592B. The highest-end Kabylake graphics PCI IDs are GT4 with 0x5932, 0x593A, 0x593B, and 0x593D.
Expect the Intel Kabylake open-source Linux graphics driver support to mature over the next few months.