Locale code for Irish English?…

LocaleLocale Locale = language version, often a combination of a language code and a region code, for instance es_MX denotes Spanish as it’s used in Mexico. A list of all locales supported by WordPress in https://make.wordpress.org/polyglots/teams/ code for Irish English?
Hi, I don’t find the Irish English in the Site Language of WordPress. There is some plugging for integrating the Irish English language location? The IETF code is en-IE but always are impossible to locate in Ireland with English.