AMD rolled out a bunch of rebadged GPUs for use in OEM systems. AnandTech has an overview of the "new" Radeon 600 series, which features Polaris, Topaz and what appears to be Oland GPUs.
As for the rebadging, this is a semi-annual event driven by OEM product cycles. In short, with the shorter product cycles of OEM systems versus retail channel video cards, OEMs want to advertise the latest components when they refresh and update their systems, even when new GPUs are not available. To which NVIDIA and AMD rebrand, refresh, or otherwise re-designate existing SKUs as new OEM-exclusive parts.
So to make it quick, here's a brief overview of the new parts: