Bracket welded to the fork leg.
Would require a very skilled welder , distortion would be a big issue.
Harley XR-TT 750 with Honda CB750 discs and calipers. Brackets clamped to Ceriani forks.
Repurposed fender bosses with two 1/4" or 5/16" bolts? Don't know if I'd want to try too many panic stops.
Not sure if this has any attachment besides the clamp? Looks more than a bit flimsy.