There are only two client interfaces included in the base PostgreSQL distribution:
All other language interfaces are external projects and are distributed separately. A list of language interfaces is maintained on the PostgreSQL wiki. Note that some of these packages are not released under the same license as PostgreSQL. For more information on each language interface, including licensing terms, refer to its website and documentation.
If you see anything in the documentation that is not correct, does not match your experience with the particular feature or requires further clarification, please use this form to report a documentation issue.