contrib module is an additional feature provided as part of the source distribution but not enabled by default. These are provided either as extension modules or as additional client or server applications. These are part of the core distribution but not enabled by default, as they either provide niche functionality or are considered experimental, or in some cases used to provide backwards compatibility for features since integrated into the PostgreSQL core.
The source code for contrib modules can be found in the "
contrib/" directory of the PostgreSQL source distribution. None of the contrib modules will be built automatically, unless the "make world" target is used, in which case all contrib modules will be built. Running "
make && make install" in the "
contrib/" directory will also cause all modules to be built. However it will probably make more sense only to build those modules which are actually required.
Operating systems which provide PostgreSQL as a package generally provide the contrib modules as a subpackage, typically called "postgresql-contrib" or similar.
This is an overview of general changes to contrib modules; for details of changes to individual modules, see the respective entry for each module.