To help others who also don’t know all of the terms: 1. FDW: foreign data wrappers

https://wiki.postgresql.org/wiki/Foreign_data_wrappers

2. PL/Python: language-specific procedural language

https://www.postgresql.org/docs/10/plpython.html

Essentially, this (as I understand it) is highlighting the ways that Postgres can expose data from outside of its default table structure context via these types of functions.