Attachments in emails are displayed in the header of the email (with the number of attachments, and if we click on it, we get a small drop-down menu to get the attachment). The problem is that if we download it from here, SOGo announces the file as application/octet-stream no matter which type the file is.

If we click on the icon at the bottom of the email instead, the correct Content-Type is sent.

This is especially problematic for PDF, as we cannot open them directly (either with PDF.js in Firefox or with the Adobe plugin), unless we go at the bottom of the email