ya reckon it was a home brewed modification?
Given the fact nobody else has anything to say about it (IE first time seeing it) And given the bike had such high miles when I got it, 92000, then it probably was.
it's nice and straight, the hole lines up perfectly, and the bracket is stout enough to apply downward pressure through the pipe into the head to keep it in place, despite the pressure in the coolant system.
Can't really fault it to be honest. it might be something more people do in the future, instead of drilling the snapped bolt out of the head