these firmwares should only be used when needed by your broken console !!!) NoBD / noBT CFW's ( for console with a broken BD Logic board (symptom = Unable to boot Games / Apps from the XMB (noBD CFW), noBT cfw are for console with a damaged Bluetooth / wifi module. For a REX build it takes time anyhow as its needs an emergence of a DEX firmware update.
Currently no plans for a REBUG CFW Release fo 4.83, will keep you informed when changes.