If the site's source is correct, the Radeon RX 500 will consist not only of new Vega 10 and Vega 11 GPUs, but also some recycled Polaris cores.
In a nutshell, the high-end enthusiast cards are expected to feature Vega 10, a 14nm chip that will likely get 8GB HBM2 with a total bandwidth of 409.6GB/s, which is lower than the 512GB/s found on the Fury X card.
Vega 11 is the chip for the mainstream cards and may see GDDR5X memory or perhaps a single-stack of HBM2.
Next the site also claims we'll see a return of Polaris for entry-level cards. These may be rebrands or more efficient versions of current cores.