Where the hell is definition of struct id3_file????

In trying to learn how to use libid3, since there sems to be no 
documentatio. I am looking at soure trying to figure out how to use it. 
The first problem is the practically every call uses a pointer to a 
"struct id3_file" . Now, the problem is that there is no definition for 
id3_file structure in any .h file. I finally found it in file.c, a 
source file. How the hell are you supposed to use it in your app when 
the prototype is in a package source file?

Seems that something is really broken here.

tj