Since the initial rumors about a multi-chip module from Intel with Kaby Lake processing power and AMD Radeon graphics, there's been a lot of debate about which graphics architecture this concoction uses. Some said it's Polaris, while the naming of the final product suggests its Vega.
PC Perspective dug in deep and concludes the GPU in Intel's Kaby Lake-G is definitely more Polaris than Vega. The graphics chip is identified by AIDA64 as "Polaris 22", it doesn't support DirectX 12.1, and lacks Rapid Packed Math. The only thing that makes this custom chip lean towards Vega is the inclusion of HBM2 support and the “high bandwidth memory cache controller and enhanced compute units with additional ROPs”.
While this doesn't change anything in regards to how the product performs, PC Perspective suggests Intel and AMD should both be criticized for mislabeling the architecture/branding.
These are tough choices for companies to make. AMD loves having the Vega branding in more products as it gives weight to the development cost and time it spent on the design. Having Vega associated with more high-end consumer products, including those sold by Intel, give them leverage for other products down the road. From Intel’s vantage point using the Vega brand makes it looks like it has the very latest technology in its new processor and it can benefit from any cross-promotion that occurs around the Vega brand from AMD or its partners.
Keep reading about the debate of Polaris vs. Vega for the KBL-G part from @Intel. On one hand, both @Intel and @AMD should be criticized if they are mis-labeling the architecture/branding on the part. OTOH, it has near-zero impact on the perf and capability of the CPU.