I was drawn by the name of kedondong. The English name is hog plum or Ambarella (scientific name: spondias dulcis).
The fruit is eaten raw, and the flesh is crunchy and sour. It reminds me of the taste of green mango, although the latter can be at times less crunchy, more sweet and more sour than the hog plum. The skin is leathery and peeled off before it is eaten, and extracted into juice.
This particular Ambarella is seedless and measures about 4-5cm in length.