Many sources refer to the use of the "SHA3" cryptographic hash function within Ethereum, but the Ethereum project began before the SHA3 standard was finalised, and there was some confusion/controversy around the final parameters selected for the standard. Which function specifically did Ethereum actually end up with? Is it the same as the actual SHA3 standard, or one of the variants within the standard? Or is it a parameterisation of Keccak that doesn't match any of the variants?