<key name="debug-exceptions" datatype="boolean" default="off">
<description>
This switch controls how exceptions are handled. If it is set to
"off" (the default), Zope's own exception handling is active.
Exception views or a standard_error_message are used to handle them.
If set to "on", exceptions are not handled by Zope and can propagate
into the WSGI pipeline, where they may be handled by debugging
middleware.
This setting should always be "off" in production. It is useful for
developers and while debugging site issues.
</description>
<metadefault>off</metadefault>
</key>
Add support for the new debug-exceptions flag: