According to the documentation of sys.tracebacklimit, setting it to 0 or less would assure "all traceback information is suppressed and only the exception type and value are printed".

This is not the case:

    $ python -c "import sys; sys.tracebacklimit = 0; raise Exception()"
    Exception

    $ python3 -c "import sys; sys.tracebacklimit = 0; raise Exception()"
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    Exception