The Tektro Auriga Twin's are one lever feeding two brakes.
I'm assuming the lever has been tweaked to pump twice the oil for a standard pull.
Otherwise the braking would be poor/weak.
I use them on my Sprint.
I think the reason for the X joint is to stay strictly within the letter of the law that both brakes on a single axle must be linked and work together.
That's how it's worded for motor vehicles.
Without a tweaked lever then you need 2 levers to feed twin brakes.
I'm not sure for trikes if that law is applicable, has been changed or if it's just ignored.
Luck .......