Why is the New York Stock Exchange closed on June 19?

Could you elaborate on the reasons behind the closure of the New York Stock Exchange on June 19th? Is it a regular holiday, a special event, or a technical issue? It's intriguing as the NYSE typically remains operational throughout the year. If it's a holiday, which one specifically? And if it's a technical issue, has the exchange provided any details or updates on the matter? Understanding the reasons behind such a closure is crucial for investors and traders to plan their strategies accordingly.