Those strange bolts reminded me of the structural bolts/nuts used to put up steel buildings these days. The tool used turns the bolt into the nut, which is held by a hex-shaped recess in the tool. Once the bolt reaches its required torque, it snaps off and you are done! The hex opening in the picture of the bolts might be used for a similar purpose - especially if spaces are tight - which I think is often true in the aircraft-making industry.