Ubuntu & Debian Abandon Intel X.Org Driver For Most Hardware, Moves To Modesetting DDX
For Intel "Gen4" hardware and newer (anything past the i965GM era), the generic modesetting DDX driver with GLAMOR is used rather than the long-standing xf86-video-intel DDX driver. The Debian/Ubuntu developers decided to make this change for Debian unstable and Ubuntu 16.10 given that the xf86-video-intel driver hasn't seen a stable update in almost three years (the long-in-development v3.0 release) and basically Intel hasn't been investing many resources at all into this X.Org driver.
Now all relevant Intel hardware will be using xf86-video-modesetting, which accelerates 2D operations over OpenGL using the generic GLAMOR module -- the same approach used by the xf86-video-ati/xf86-video-amdgpu drivers for GCN and newer and optionally older hardware too. So that should benefit with greater GLAMOR test coverage now as an added bonus.
More commentary about the Intel DDX driver going away on Debian-based distributions except for very vintage Intel IGPs, see Timo Aaltonen's blog, one of the graphics developers at Canonical.