What exact debugging information is added to the binary and how to parse it all?

[BoQsc via Digitalmars-d-learn]

Haven't used debuggers or debugged a lot just yet, but I've had 
this question in my mind and I'd like to inspect some debugging 
information manually. Are there some kind of documentation or 
specification and are there a lot of information that is hidden 
in a an average "debuggable" binary?