This GPU is expected to be used for the new flagship from AMD, which will reportedly be named Radeon RX 6900 XT. There's no HBM2 around the die so this is pretty much confirmation of the use of GDDR6 series memory.
As always, take this information with a grain of salt. Coreteks mentions a transistor count of 26.3 billion transistors for Navi 21 and a core clockspeed of up to 2.2GHz. For comparison, NVIDIA's GeForce RTX 3080 packs 28 billion transistors. Other leaked specifications that are making the rounds point to 80 CUs for Navi 21 and 16GB GDDR6 memory.
AMD's official announcement of the Radeon RX 6000 series is planned for October 28.