it's got a tummy button but everyone knows that dragons have eggs....
But surely, even in an egg, the cute ickle foetal dragon would need something to attach it to the yolk? Hence the umbilicus. Crack open a humble chicken egg and you'll see the white stringy proto umbilical cord hanging off the yolk sac and waiting for a chicken foetus to grow on the end of it.
Of course, they're only telling us it's fake because they don't want us knowing it's actually real.