It was a bit of a mistake, as shortly thereafter they removed it, but their website had a placeholder for the 6600. And that means a launch is imminent and likely closer than expected.

No specs of the video cards are given in the webpage and is no particular Radeon RX 6600 model on the PowerColor website, although there are list categories for RX 6600 and RX 6600 XT cards. We know nothing more about the GPU series, however speculations regarding video cards have been there for some time. Navi 23 is expected to be the GPU for these graphics cards. The desktop Radeon RX 6600 XT would contain a 32-compute units, which is good for 2048 stream processors. Then GDDR6 8-GB memory with a 128-bit memory bus and 16-Gbit/s speed would be provided. This is good for 256GB/s bandwidth. THe card will also include 32MB Infinity Cache. A Navi 23 GPU with 28 compute units and 1792 stream processors would be the the Radeon RX 6600.

PowerColor Mentions Radeon 6600 GPUs on website