Since RDDRONE-FMUK66 Rev. C, this connector is not found on the board anymore. The newer FMUs now have a 10 pin connector for the Pixhawk 4 GPS, which has a buzzer inside. There is also no separate buzzer is included in the HoverGames kit anymore.
This is a piezo buzzer attached to a two pin JST-GH type connector.
Polarity is not critical.
The buzzer cable looks like the image above when completed.
It can be made quickly:
1x 2 pin JST-GH housing.
1x 6" JST-GH pre-terminated wire.
1x Piezo buzzer.
Cut the 6" JST-GH pre-terminated wire in half.
Strip 5mm off the cut ends of the JST-GH wire you just cut in half, and add tin using a soldering iron.
Solder the JST-GH wire to the stripped and tinned Buzzer wires.
Apply heatshrink over each of the solder joints.
Poke the crimped end of the JST-GH wire into the two pin housing.
The order does not matter, but for consistency the red buzzer wire should go to pin 1.