Noss, I think it's a major misspelling of the name. But like John shows in his more info section, the names are "also known as". JR call it Galbun and I have 2 of his trees. UCD calls it Gulbun. To me, researching figs is like doing your family tree. There are known sources of a name but are they the same? Yes!
For example, my grandmother on my mom's side was full blooded American Indian. For years, no one ever could prove she American Indian until I spent weeks searching the US archives. Her maiden name was Bohannon. Her dead certificate spells it Bohannan. But the US Census of Oklahoma from the Choctaw 5 Civilized Tribes back in 1930 spells her name as Irene Bohanan. So, which name is correct? To me, they all are correct and the same goes for figs. All of the names sound the same. But when folks start writing down the name, that's were we start to see how they spell it.
HOW BOUT THOSE FIGS!!!!!