You had an uncaprified(Unpolinated),Breba fig,that fell off from lack of polination,in your climate,that was what it was.
If you look more carefully you will find out it was growing on old wood.
That was a female flower,(breba),that need polination to grow and get ripe.
Mule Flower,grow and ripe unpolinated,and are found usually,but not allwayes on the main crop,that grow on new growth,for the current year.
It is very complicated,because every cultivar is different,as for the number of Females,and mule flowers,and when,they appear,on breba or main crop.
H2