The information comes from macOS firmware updates from AMD:
AMD Navi 22 GPU is not a mystery to us anymore. Similarly to Navi 21 and Navi 23, it leaked through macOS firmware updates, which confirmed that the GPU features up to 40 Compute Units. This is the same CU count as the Navi 10 GPU from the previous RDNA generation. What this means is that the upcoming Radeon RX 6700 series will succeed the RX 5700 series with the same core count, but with all the power efficiency, higher clock speeds the cards are expected to be noticeably faster.AMD is reportedly also working on a mobile version of the Navi 22 GPU.
It's also possible that NV22 XTL has a lower min. TGP than 146 W. I'm not 100 % sure about that. So far I haven't seen any NV22 XTL with less than 146 W TGP.— Patrick Schur (@patrickschur_) November 21, 2020