As mentioned in my article, the Intel Linux Vulkan driver isn't based upon LunarG's original open-source driver prototype they did for Valve. Their new driver for Linux is Vulkan 1.0 conformant and was written in-house by Jason Ekstrand, Wayland creator Kristian Høgsberg Kristensen, Chad Versace, and others over the past year.
The initial code to the branch is in this Vulkan Mesa branch. The files within src/vulkan amount to around 36k lines of code, excluding tests. This Vulkan Mesa code is designed just around the Intel driver and isn't using Gallium3D or the like. A lot of the code is prefixed as anv_ and appears to stand for a new "Anvil" name. Intel developers have already said that not a lot of this driver code can be easily shared with other drivers.
The open-source Intel Vulkan driver is officially supporting Broadwell, Braswell, and Skylake graphics hardware. With those latest architectures, that's where they have Vulkan 1.0 conformance but it should work on hardware all the way back to Ivy Bridge but with possible issues.
The Intel Vulkan driver is living in Mesa as they are utilizing the same NIR core common to their Mesa DRI driver as well as the same compiler back-end. They added in a SPIR-V to NIR pass and other changes for bringing Vulkan support.
More details can be found via this 01.org post. Ubuntu and Fedora packages are in the process of being built via third-party archives (PPA and Copr, respectively) for those wanting to try out Vulkan 1.0 on modern Intel graphics hardware.
With the Mesa 11.2 branching set to happen Friday, Intel will be working on upstreaming the core to mesa in the next few weeks. The next Mesa release will come in 3~4 months time. The Intel Vulkan driver does depend upon DRI3 rendering support, where as DRI2 is the default, so you must manually enable Direct Rendering Infrastructure 3 if wishing to try out this driver.
I'll be testing out the Intel Vulkan Linux driver when I move on with the Vulkan benchmarking plans.