"₴" - "\u20b4"
"грн" - "\u433 \u0440\u043d"
В файле /translations/cldr/mail-xx-XX-currencies находите описание гривны
"UAH": {"displayName": "\u0423\u043a\u0440\u0430\u0438\u043d\u0441\u043a\u0430\u044f \u0433\u0440\u0438\u0432\u043d\u0430", "displayName-count-one": "\u0443\u043a\u0440\u0430\u0438\u043d\u0441\u043a\u0430\u044f \u0433\u0440\u0438\u0432\u043d\u0430", "displayName-count-few": "\u0443\u043a\u0440\u0430\u0438\u043d\u0441\u043a\u0438\u0435 \u0433\u0440\u0438\u0432\u043d\u044b", "displayName-count-many": "\u0443\u043a\u0440\u0430\u0438\u043d\u0441\u043a\u0438\u0445 \u0433\u0440\u0438\u0432\u0435\u043d", "displayName-count-other": "\u0443\u043a\u0440\u0430\u0438\u043d\u0441\u043a\u043e\u0439 \u0433\u0440\u0438\u0432\u043d\u044b", "symbol": "\u20b4", "symbol-alt-narrow": "\u20b4"}
Меняете знак
"symbol": "\u20b4"
на буквы
"symbol": "\u433\u0440\u043d"