A custom magic database for use with libmagic (www.darwinsys.com/file). The main purpose of maintaining the separate database is so that results are more deterministic and independent from the particular version of libmagic that's installed, which comes with its own default database. It also allows file type patterns to be added/updated/removed more quickly/flexibly.
The database is currently the default one shipping in libmagic 5.16 with few modifications. Differences are listed in patches/ directory.