It's hardcoded to be broken in too many devices. NANOG has long and winding threads about reclaiming the class E space - there was consensus that it wasn't poss

It's hardcoded to be broken in too many devices. NANOG has long and winding threads about reclaiming the class E space - there was consensus that it wasn't possible to get enough devices unbroken for the space to actually be usable. IIRC, a lot of networking equipment chokes on it.