fix: Correct HTML lang attribute in source. closes #6534

shared/utils/date.ts

@@ -106,6 +106,16 @@ export function unicodeBCP47toCLDR(locale: string) {
   return locale.replace("-", "_").replace("und", "root");
 }
 
+/**
+ * Converts a locale string from Unicode CLDR format to ISO 639 format.
+ *
+ * @param locale The locale string to convert
+ * @returns The converted locale string
+ */
+export function unicodeCLDRtoISO639(locale: string) {
+  return locale.split("_")[0];
+}
+
 /**
  * Returns the current date as a string formatted depending on current locale.
  *