https://www.vice.com/en_us/article/qj89ed/mcdonalds-accepts-bitcoin-in-el-salvador-as-crypto-becomes-official-currency

El Salvador's "Bitcoin Law" went into effect on Tuesday, marking the launch of the historic and controversial bid to make the Latin American country the first in the world to make cryptocurrency officially-recognized money along with the US Dollar.

As for what that actually means, it seems you can now buy a meal at McDonald's in the country's capital with Bitcoin.