This is libkml, Google's library for use with applications that want to parse, generate and operate on KML. It is an implementation of the OGC KML 2.2 standard.
It is written in C++ and bindings are available via SWIG to Java and Python.
A basic guide for our 1.2 release is here.
Atom feeds for project updates are linked here.
These details are provided for information only. No information here is legal advice and should not be used as such.