The possibly of a stablecoin being used by billions of people - think of Facebook's (FB) Libra - is spurring central banks to put together rules that would govern the currency.Stablecoins are an attempt to address the high volatility of "traditional" crypto-assets by tying the stablecoin's value to one or more other assets, such as sovereign currencies.The latest? The Financial Stability Board, which groups central banks and financial regulators from the G20 economies, has agreed to build a roadmap to enhance cross-border payments, flexibility, efficiency and coordination:"Completion of international standard-setting work by December 2021.""Establishment or, as necessary, adjustment of cooperation arrangements among authorities by December 2021 (and as needed based on market evolution).""At a national level, establishment or, as necessary, adjustment of regulatory, supervisory and oversight frameworks consistent with the FSB recommendations and international standards and guidance by July 2022 (and as needed based on market evolution).""Review of implementation and