4Pool in Polygon

Just seen 4Pool in Polygon and the swaps are to Frax, UST , amUSDC and amUSDT.
I’m confused why amUSDC / amUSDT, why not the USDC and USDT?

I tried to use amUSDC in AAVE but there’s no deposit option for the amUSDC ust the USDC.

Anyone knows anything about the amUSDC and amUSDT?