>>1649001it's a system shimano invented because mtbs sometimes snapped their front brake cable and then it would drop onto the tyre, catch on the knobs, and send the rider over the bars. It's called a link wire.
Personally I think link wires fuck up brake feel a bit and that they aren't necessary for safety unless you're really aggressively riding in which case well why cantis. You can also do pic rel if you're worried
