As a result this proxy can verifiably support token functionality in its ABI if it sits in front of an ERC20-compliant smart contract. Apart from these functions, ProxyERC20 operates identically to the proxy it inherits.
In the Synthetix system, an ERC20 proxy operates in front of the main SNX token contract, alongside the pre-existing standard proxy. Thus clients can choose to use either of these two proxies to interact with the system.
This contract defines all ERC20 functions, including
decimals(). These functions simply call down to the underlying token contract.