In the attachment a xlsx file with two cells and one of them created by POI.
TestVisibleComment - Copy.xlsx (application/vnd.openxmlformats-officedocument.spreadsheetml.sheet), 8.37 KB, created by ORLANDI on 2016-04-27 14:31:52 UTC
Creator: ORLANDI
Created: 2016-04-27 14:31:52 UTC
Size: 8.37 KB

Attachment is not viewable in your browser because its MIME type (application/vnd.openxmlformats-officedocument.spreadsheetml.sheet) is not one that your browser is able to display.

Download the attachment.

Actions: View
Attachments on bug 59388: 33812