This design is installable without the need to untie the brake handle and does not damage your lines but the installation is a bit tricky.
you will need two M3x14mm hexagon socket head cap screws and two M3 nuts.
to insert the nuts I used a soldering iron as in the picture :
To prevent the sphere from sliding on the line, I wrapped a piece of fabric between the line and the sphere.
To print it you will have to activate the brim parameter and set a large brim width so that the print sticks to the bed :
The author marked this model as their own original creation.