This tool is used for debugging when an uninstalled tool does not appear in the "Explore ProTo tools" tool. This is typically due to an Python exception being raised at the import the tool module. This tool lists all modules under the tool directory that cannot be imported due to an exception. When selecting the tool, a traceback of the exception is shown. One can also click "Execute" to store the exception within a history element (which will then become red). This is useful if one wants to send a bug report for the exception, or if one wants to keep a backlog of the error messages.