(Late Edit: the above comment was rather sloppy. I meant that we don't know if it's impossible to prove BB(748)=X in ZFC+Con(ZFC). It's not necessarily possible

(Late Edit: the above comment was rather sloppy. I meant that we don't know if it's impossible to prove BB(748)=X in ZFC+Con(ZFC). It's not necessarily possible either. We just haven't ruled out the possibility.)