Repository (CLDR) refers to zones in the tz database. However, as the name for a zone can change from one tz database release to another, the CLDR assigns the UN/LOCODE for the city used in the name for the zone, or an internally-assigned code if there is no such city for the zone, to a tzdb zone. Use in software systems The tz database is used for time zone processing and conversions in many computer software systems, including: BSD-derived systems, including FreeBSD, NetBSD, OpenBSD, DragonFly BSD, macOS, and iOS (they also use the reference TZ database processing code as their TZ POSIX API implementation); the GNU C Library and systems that use it, including GNU, most Linux distributions, BeOS, Haiku, Nexenta OS, and Cygwin; System V Release 4-derived systems, such as Solaris and UnixWare; AIX 6.1 and later (earlier versions of AIX, starting with AIX 5.2, include zoneinfo, for support of third-party applications such as MySQL, but do not use it themselves); Android several other Unix systems, including IRIX, Tru64, SunOS 4.x, and UNICOS/mp; OpenVMS; the Java Runtime Environment since release 1.8 (2014), see java.time.ZoneId the Perl modules DateTime::TimeZone and DateTime::LeapSecond since 2003; PHP releases since 5.1.0 (2005); the Ruby Gem TZInfo; the Python standard library zoneinfo module, and the third-party pytz package; the JavaScript language specification for Internationalization explicitly specifies the usage of IANA Time Zone names for API, and recommends the usage of the time zone data as well. Numerous libraries also available: timezone-js, BigEasy/TimeZone, WallTime-js and moment-timezone; the Pandas (Python) module pandas – Python Data Analysis Library; the .NET Framework libraries NodaTime, TZ4Net and zoneinfo; the Haskell libraries timezone-series and timezone-olson; the Erlang module ezic; The Go standard library time package; The Rust crate chrono-tz; The Squeak Smalltalk time package; The C++ libraries Boost and Qt, and C++20 chrono standard library's std::chrono::tzdb; The Delphi and Free Pascal library TZDB; The Free Pascal library PascalTZ; The Tool Command Language has a clock command using tzdata; Oracle releases since 10g (2004); PostgreSQL since release 8.0 (2005); the Microsoft SQL Server library SQL Server Time Zone Support MongoDB since release 3.6; embedded software such as the firmware used in IP clocks. The Olson timezone IDs are also used by the Unicode Common Locale Data Repository (CLDR) and International Components for Unicode (ICU). For example, the CLDR Windows–Tzid table maps Microsoft Windows time zone IDs to the standard Olson names, although