Explanation:
This design was installed on a touring road bike I bought used around 2010. The previous owner wanted to have hydraulic brakes on his road bike, but either this didn’t exist at the time, or he couldn’t afford it.
The mechanical brake line leads from the brifters to an aluminum stopper, which barely hangs on to the stem by a zip tie.
The inner brake cable is fed through a hollow screw and holes in the aluminum part, and pulls on the (sawed-off, free-hanging) Magura brake lever, which then actuates the hydraulic brake.

It worked about as well as it looks. I replaced the whole shebang with mechanical 105 which massively improved the braking performance.