Not sure of the acronym but it is a repository of collected user generated art for tokens and other objects for maps. When somebody makes a table or a chair they often upload it to their fav mapping program forum and the forums usually have a licencing statement which allows other users to download it for their own use. Sometimes thats for commercial use too and they might even have something more formal like a "Creative Commons" licence which specifically allows certain rights.

Anyway, some dudes went around sucking them all up from different websites, sorting and blocking them into zips of similar objects which were free to use. I think some of them said that they would not like the wholesale zips uploaded and redistributed tho (for some reason). Well, as usually happens in those situations, the original dudes website became obsolete but other people have popped up to continue marching on holding the standard.

I think thats mostly correct but might have some slight errors in it.