Comment 21 for bug 1313550

So yeah, my understanding is that --xattr is broken at the moment, we should fix that as an SRU but we also have the problem that:
 1) It's not set by default in either create or extract mode
 2) Not all tar implementations we use support it
 3) Not all version of gnu-tar we support have it

So as long as we don't get this fixed, we shouldn't rely on xattrs working in tarballs and should investigate alternative methods of shipping and setting those attributes.