http://vww6ybaluuo4gfuuf6zvlt23hvg2pcfayco5iiwhv3plo6o7bewivoid.onion/ca/lists/list-admin/faq
Unfortunately, this means that some people don’t see it. To change the type, go to the list’s admin page and there under “Edit List Config” → “Sending/reception” you can change the “Attachment type” option from “mime” to “append” .