The XLB file isn't in a text format like XLS files are, so you can't convert it to any other usable format like XLS, XLSX, etc.
File XLB adịghị na ederede ederede dị ka faịlụ XLS, ya mere i nweghị ike ịtụgharị faịlụ XLB na ụdị ọ bụla nwere ike iji dị ka XLS, XLSX , wdg.