curl --request GET \
  --url https://gateway-api-testnet.circle.com/gateway/v1/x402/supported

{
  "kinds": [
    {
      "x402Version": 123,
      "scheme": "<string>",
      "network": "<string>",
      "extra": {
        "name": "<string>",
        "version": "<string>",
        "verifyingContract": "<string>",
        "assets": [
          {
            "address": "<string>",
            "symbol": "<string>",
            "decimals": 123
          }
        ]
      }
    }
  ],
  "extensions": [
    "<string>"
  ],
  "signers": {}
}