Word Break - Regional Indicator

Regional Indicator is a special character class used in text segmentation to represent the two letter codes, typically uppercase A through Z, that combine in pairs to form emoji flag sequences. When two Regional Indicator characters appear consecutively, they are treated as a single grapheme cluster, representing a country or region flag, such as the United States or Japan. If an odd number of these indicators occurs, the extra one is handled as an unpaired, standalone character for line breaking and cursor movement, preventing the flags from being split across lines or edited as separate units. This behavior ensures that flag emojis remain visually and logically intact during text processing.