contains file format information on hundreds of different file types and all sorts of other useful programming information; algorithms, source code, specifications, etc.
tries to cover every single aspect of tracking, every single tracker, and every single machine available ever. It's intended to become the most comprehensive guide to tracking ever made, and a one-stop source of help for every level of tracker out there.
a general purpose library and file format for storing scientific data. It arranges data into datasets (multidimensional arrays) and groups (a structure for organizing objects). With extra software support like a viewer, etc...
a library for reading and editing the meta-data of several popular audio formats. Currently it supports both ID3v1 and ID3v2 for MP3 files, Ogg Vorbis comments and ID3 tags and Vorbis comments in FLAC files.