A kumquat with the text “#1” stamped on it: found this way in the bag.
Wow! The first kumquat ever produced. You can fetch good money from collectors.
Kumquat Werbenjägermanjensen
I have never seen kumquats in the store. We have a small tree, so we get more than we need and I’m unlikely to buy any, but I’ve never seen them.
Also, is that typical of the way they look where you are? Ours look like these.
In citrus fruits sometimes ripe fruits will turn orange and then turn green again (either all over or in patches), it’s called regreening. It’s usually due to either chilly night temperatures or high UV exposure, so the same tree might produce completely orange or orange and green or completely green ripe fruit all in the same year.
Kumquats are taxonomically weird and may or may not be citruses, so I’m not sure that’s what’s happening in the OP, but I would guess it probably is.
It wasn’t as much the color as the shape I was commenting on. OP’s looks like a ball, but I’ve only seen them oblong (I’ve heard that “quat” means something like “pear shaped”).
I’ve never seen them in a store here in New Zealand. I’ve been trying to grow them, but while the tree is doing well it is yet to produce fruit.
I did manage to buy some at a supermarket in Berlin a few years ago while on holiday, they were packed like cherry tomatoes in a clear plastic punnet.
The egg-shaped fruit you’ve got are frequently the “Meiwa” or “Nagami” cultivars, OP’s round fruit may be the “Marumi”.
This does look like it was printed on the kumquat. I don’t know whether it’s the case here, but this sort of thing sometimes happens when there is something printed on a bag or the plastic that food is wrapped in, and the ink can get transferred to the food.