Abstract: A fenestration unit configured to support a shootbolt locking system includes a panel including a panel frame with a stile member and a rail member that are attached by a corner joint. The stile and rail members are elongate and extend along a respective linear axis. The stile member is configured to receive and support at least part of the shootbolt locking system. The stile member includes a stile end with a first wall, and the rail member includes a rail end with a second wall. The corner joint includes a first bracket and a second bracket that are attached together. The first bracket is disposed within the stile end. The first wall is disposed between the first and second brackets. The second bracket projects away from the stile member, and the second bracket is received within the rail end and attached to the second wall.