3-Current instructions ask for reporters to add the traces as an attachment. I've noticed that bugzilla recognizes such text files as binary files.
Also, I've seen reports where traces shows up in the description, expandable in line, instead of being an ordinary attachment. Example: https://bugzilla.gnome.org/show_bug.cgi?id=594425 I don't know how to do that, but it looks like something we should instruct reporters to do instead.