As with other tools, you can configure the way package names are displayed in the debugger tool in the Package panel of the Debugger Preferences dialog.
Check Show Package Names to turn the display of package names in the Backtrace and Variables lists on and off.
Specify a package name in the text box to change the process package of the debugger tool. Click on 
to complete the package name as far as possible. By default, the current package is the same as the package from which the error was generated.