Here is a list of all documented files with brief descriptions:

oggplay.h	The liboggplay C API
oggplay_callback_info.h	Oggplay_callback_info.h
oggplay_enums.h	General constants used by liboggplay
oggplay_query.h	Oggplay_query.h
oggplay_reader.h	Oggplay_reader.h
oggplay_seek.h	Oggplay_seek.h
oggplay_tools.h	Oggplay_tools.h