Very brief introduction mostly for Mac OS X users,
The TeX wrapper is just a folder where one gathers everything
related to a single document: text, images, macros, whatever
In the Info.plist file (an xml property list format widely
used by Mac OS X), you will find general purpose meta data like
the master document name and the file encodings, eol, language.
An indirection table is used to manage properly the changes of
In the frontends folder, different front ends will store their
private metadata, in a file or a folder, whatever they want.
Maybe some confidential per user info might be interesting, this feature is copied from XCode.
The actual file specifications are available as part of the article I wrote for TUG 2004.
These specs are not closed in the sense that frontends must be very careful and smart in using them: they might be corrupted!