It’s the original codename for this standard.
https://github.com/smartcontractkit/ccip-read/tree/rewrite
Ethers throws an exception with error information in the exception object. See the ethers provider plugin in the above repository for a way to handle EIP 3668 contracts transparently to the JS code.
That’s right. All of this can be handled transparently for the user via the web3 library, however.