The legacy `JRE` locale data has been removed from the JDK. The legacy `JRE` locale data, `COMPAT` is an alias for this locale data, remained after the `CLDR` locale data based on the Unicode Consortium's [Common Locale Data Registry](https://cldr.unicode.org/) became the default with JDK 9 ([JEP252](https://openjdk.org/jeps/252)). The `JRE` locale data served as a tool to migrate applications for the time being. Since JDK 21, users have been notified of its future removal with a startup warning message as the use of `JRE`/`COMPAT` locale data was deprecated. It is now removed from JDK 23, so specifying `JRE` or `COMPAT` in the `java.locale.providers` system property no longer has any effect. Applications using `JRE`/`COMPAT` locale data are encouraged to migrate to CLDR locale data or consider a workaround discussed in the [CSR](https://bugs.openjdk.org/browse/JDK-8325568). [JEP 252: Use CLDR Locale Data by Default](https://openjdk.org/jeps/252) has been updated with recommendations for developers impacted by the removal of this legacy locale data.