Regional indicator symbol
The regional indicator symbols are a set of 26 alphabetic Unicode characters (A–Z) intended to be used to encode ISO 3166-1 alpha-2 two-letter country codes in a way that allows optional special treatment.
These were defined in as part of the Unicode 6.0 support for emoji, as an alternative to encoding separate characters for each country flag. Although they can be displayed as Roman letters, it is intended that implementations may choose to display them in other ways, such as by using national flags.[1][2] The Unicode FAQ indicates that this mechanism should be used and that symbols for national flags will not be directly encoded.[3]
They are encoded in the range U+1F1E6