Object data is stored as an ".a2c file". This is a compressed set of files that contains a mix of html, graphic and binary files - some of which are easily understood and some of which, like the binary mesh files, are very difficult to decipher.

Everything about the object - methods, parameters, mesh and texture date, etc. is stored in the one compressed directory.

For more information, I would suggest a search of the forum - however most of the information (at least that I've found) is specific to a particular part of the file - there is really no good overview or overall specification.

For decompressing the file, I recommend 7-zip instead of WinZip - I also believe you can decompress with WinRar, although I haven't tried that recently.