Issues with attachments of type "other"
When downloading attachments of type "other", the suggested filename will have a generic ".bin" extension. This renaming is done by the Pump.io core. However, Dianara will show the mime type (like application/pdf or application/x-gzip), so users can still know what type the file is, and name it accordingly when saving.
Other users will not be able to download these kind of attachments unless they are on the same server as the person who posted them, or the post is public. This is due to a missing field on the data provided by the Pump.io server.
See pump.io issue: https://github.com/e14n/pump.io/issues/1014
Keep in mind that, as of this writing, most Pump clients, including the web interface, are not aware of attachments of type "audio", "video" or "file" (other). They only know about "image" attachments.