That, my friend, is what they call a ´mataperro´ - a ´dog killer´
Apparently a motorcycle so equipped can quickly shrug off a dog attack; perhaps even gently brush aside a cow or a horse in the road. I hear accounts of lives saved by the mataperro in the ancient folk stories of the indigenous peoples here.
It´s where you would mount your forward pegs if anyone used them here - tubular steel bolted to the frame. My father-in-law shoves his plastic thermos filled with ice water in there after he wraps it with a plastic bag to keep all the sand and diesel fumes out. He also wraps some bailing wire and straps some inner tube pieces to it just in case something falls off.
It really is, by the way, called a mataperro and the proper translation truly is dog-killer.