They are bracing bars from the block to the gearbox,
If it's sheared the head off take the bar off and see if you get the rest of the bolt out with multi-grips or pliers then just replace the bolt
If that's not going to work then try drilling it out or use easy-outs etc.
I've got rid of one of them on my CG13 as have others that have put them in minis, no problems so far...
I wouldn't worry if you can't get the bolt out.
