The variable *default-timezone* contains the timezone that will
be used by default if none is specified. It is loaded from
/etc/localtime when the library is loaded. If
/etc/localtime is not present, it will default to UTC.
— Constant: +utc-time+
The variable +utc-zone+ contains a timezone corresponding to
UTC.
Define zone-name (a symbol or a string) as a new timezone,
lazy-loaded from zone-file (a pathname designator relative to
the zoneinfo directory on this system. If load is true, load
immediately.