Extract the answer to the question from the following context. Question: What's used? Context: However, even if UTC is used internally, the systems still require information on time zones to correctly calculate local time where it is needed. Many systems in use today base their date/time calculations from data derived from the IANA time zone database also known as zoneinfo.
A:
date/time calculations from data derived from the IANA time zone database also known as zoneinfo