Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 39998)
+++ wp-includes/formatting.php	(working copy)
@@ -1694,6 +1694,14 @@
 
 		// Used for locale-specific rules
 		$locale = get_locale();
+		/**
+		 * Filters for installations that have different locale names.
+		 *
+		 * @since 4.7.2
+		 *
+		 * @param string $locale The locale ID.
+		 */
+		$locale = apply_filters('update_locale_for_remove_accents', $locale);
 
 		if ( 'de_DE' == $locale || 'de_DE_formal' == $locale || 'de_CH' == $locale || 'de_CH_informal' == $locale ) {
 			$chars[ 'Ä' ] = 'Ae';