It was bought in southern China. At first I mistook it for a ripening date..same size, color and similar shape. However it has a fuzzy and thicker skin. The skin has a very green flavor, the flesh is citrus flavored. There's no pit. And the skin is attached to the meat, but can be peeled.  It's like a mix between a date (size/color), a kiwi (skin) a lemon (flavor somewhat) and a longan (flash texture).    
My best guess would be wampee fruit - has roughly the same size, shape, and stem colour, and obviously comes from the same region, although I'm not sure about the interior:    It's hard to tell from the low contrast in the photo but it could also be loquat, AKA "Japanese Plum".    Only problem with the second choice is that loquat usually has full-on brown branches as opposed to green stems - so it's probably the wampee. 