case TypeXGlobalHeader:
		h2 := Header{Name: h.Name, Typeflag: h.Typeflag, Xattrs: h.Xattrs, PAXRecords: h.PAXRecords, Format: h.Format}
		if !reflect.DeepEqual(h, h2) {
			return FormatUnknown, nil, headerError{"only PAXRecords should be set for TypeXGlobalHeader"}
		}
		whyOnlyPAX = "only PAX supports TypeXGlobalHeader"
		format.mayOnlyBe(FormatPAX)
	}