The kukri appears to be the type (known as
maar hani) used for animal sacrifice in Hindu religious ceremonies such as Durga puja/Dasein. As mross observes, it doesn't appear very old (at least from the detail visible at this low resolution) but such sacrifices are still performed at the present time. The long blade is intended to sever the head of the sacrificial animal cleanly with a single blow, an important component of Hindu sacrifice. Since Islamic sacrifice is performed by slitting the throat and jugular without severing the spinal cord or breaking the neck, I can't think of a use for this specialized ritual knife in Riyadh. Perhaps it found its way into the museum simply as an interesting ethnographic oddity?
