The blue and yellow wires and sliding jumper are present in the driver's seat belt and are not present in the passenger's seat belt. By experiment I found that the warning chime sounds when the jumper shorts the wires together and is silent when the jumper is moved to where it no longer shorts the wires together. Snipping one of the wires silences the chime.
Does it also affect operation of the air bag system or seat belt pretensioner? Only Hyundai knows for certain. I surmise that it doesn't for these reasons:
There are air bags on both sides of the car, but the blue and yellow wires are only on the driver side.
There is another pair of wires going to some sort of sensor in the seat belt buckle, and this is on both passenger and driver sides. My deduction is that that sensor is tied into the safety systems, and the seat belt warning chime uses a separate sensing mechanism because the safety regulators expect people to try to disable it and don't want the operation of the air bag system to be affected when they do so. But that's just my deduction.
If the air bag system did rely on the blue and yellow wires, snipping them would cause it to act as if the seat belt was fastened even if it was not fastened. The air bag system might be designed to deploy more slowly if the seat belt is fastened. If your seat belt is unfastened when the air bag deploys, causing it to falsely detect that your seat belt is fastened could give you less protection.
Incidentally, I asked a Hyundai dealer to silence the chime for me. He refused, saying it was "safety equipment" and it was "not possible". If you want to silence that annoying chime, you'll have to do it yourself.