# 11 one of the lower front mount bolts that goes into the midsection. Good news is you can probably remove the clamp assembly by the single outer mount nut [# 13] & the top side mounts. From there you can get at the bolt to remove.
Well, there isn’t much to work with there, probably isn’t much of the broken stud sticking out of the exhaust housing. Remove the mount and use vice grips and some heat to coax it out, otherwise you will have to drill it out…Not so easy on those SS screws….