at this point it's probably never gonna get fully released but I still wonder what exactly it was
supposedly Master Quest is PART of Ura Zelda (namely it's remapped dungeons) but not all of it
supposedly the actual version of Ura Zelda was like Majora's Mask in a couple ways, apparently despite having the same storyline as OOT, EVERYTHING was supposed to have been remapped (which may be why Master Quest's overworld was mirrored, as a way of making it feel like they remapped the whole game when they really hadn't) and there may have even been supposed to be a few additional dungeons and sidequests (the game was apparently bigger than regular OOT which is why it required the N64DD)
either way Ura's remapped dungeons are the only portion of the game that ever saw a release, in the form of Master quest