* Controls whether mailboxes appear in the Django Admin.
*``DJANGO_MAILBOX_SKIPPED_EXTENSIONS``
* Default: ``['.p7s']``
* Type: ``list``
* A list of extensions to skip when processing e-mail message attachments.
*``DJANGO_MAILBOX_STRIP_UNALLOWED_MIMETYPES``
* Default: ``False``
* Type: ``boolean``
* Controls whether or not we remove mimetypes not specified in ``DJANGO_MAILBOX_PRESERVED_MIMETYPES``.
*``DJANGO_MAILBOX_ALLOWED_MIMETYPES``
* Default ``['text/html', 'text/plain']``
* Type: ``list``
* A list of mimetypes that will remain and be stored in the message payload of the message object. Has no effect unless ``DJANGO_MAILBOX_STRIP_UNALLOWED_MIMETYPES`` is set to ``True``.
