I just copied a load of the code from the built in help files, and so some of that code is left over.
Debug.Trace is a way of putting the files in the debugging box. Which you can activate by checking the option box from the scripts menu.
Developers use the trace as an easy way of finding out what is wrong with their code, for example if a bit of code such as
code:
if (Var1 == Var2) { ... }
didn't work, the developer might put
code:
Debug.Trace(Var1); Debug.Trace(Var2);
so they can find out if the variables are indeed the same.