is not necessarily correct for the entire region. This is because new regions are created only as required to distinguish clocks since 1970. For example, between 1963-10-23 and 1963-12-09 in Brazil only the states of Minas Gerais, Espirito Santo, Rio de Janeiro, and São Paulo had summer time. However, a requested split from America/Sao_Paulo was rejected in 2010 with the reasoning that, since 1970, the clocks were the same in the whole region. Time in Germany, which is represented by Europe/Berlin, is incorrect for the year 1945 when the Trizone used daylight saving time rules different from Berlin's. Coverage Zones covering multiple post-1970 countries There are two zones that cover an area that was covered by two countries after 1970. The database follows the definitions of countries as per ISO 3166-1, whose predecessor, ISO 3166, was first published in 1974. Asia/Aden – two countries until 1990: North Yemen (ISO 3166-1: YE; capital Sana'a) and South Yemen (People's Republic, ISO 3166-1: YD, ISO 3166-3: YDYE; capital: Aden). Europe/Berlin – two countries until 1990: East Germany (ISO 3166-1: DD, ISO 3166-3: DDDE) and West Germany (ISO 3166-1: DE) Maintenance The tz reference code and database is maintained by a group of volunteers. Arthur David Olson makes most of the changes to the code, and Paul Eggert to the database. Proposed changes are sent to the tz mailing list, which is gatewayed to the comp.time.tz Usenet newsgroup. Source files are distributed via the IANA FTP server. Typically, these files are taken by a software distributor like Debian, compiled, and then the source and binaries are packaged as part of that distribution. End users can either rely on their software distribution's update procedures, which may entail some delay, or obtain the source directly and build the binary files themselves. The IETF has published , "Procedures for Maintaining the Time Zone Database" documenting best practices based on similar principles. Unix-like systems The standard path for the timezone database is /usr/share/zoneinfo/ in Linux distributions, macOS, and some other Unix-like systems. Usage and extensions Boundaries of time zones Geographical boundaries in the form of coordinate sets are not part of the tz database, but boundaries are published by Eric Muller in the form of vector polygons. Using these vector polygons, one can determine, for each place on the globe, the tz database zone in which it is located. Use in other standards The Unicode Common Locale Data