If a relevant error log object is found, exceptions included in the error log's ignored exception types will be ignored and the debugger won't be invoked.

It also enables the import of the pdb module in unprotected code.

On encountering an error, the port-mortem debugger is invoked with the error's traceback. Once in the debugger you can examine objects, variables, etc. at all levels of the call stack. This is, of course, extremely useful for debugging.