Per the debugger spec: https://wiki.mozilla.org/Debugger decompile([pretty]) Return a string containing JavaScript source code equivalent to this script in its effect and result. If pretty is present and true, produce indented code with line breaks. (Note that Debugger.Object instances referring to functions also have a decompile method, whose result includes the function header and parameter names, so it is probably better to write f.decompile() than to write f.getFunctionScript().decompile().)

The documentation is currently listing this method without any further comments, shouldn't it be marked as "future plan"?