It's a joomla library which contains some JForm fields which I use in my extensions and want to share.
Note It can be used only by developers, regular users cannot use it meaningfully.
The main purpose is to allow having self-reproducing fileds or group of fields (though there are some other useful fields included). It can be used especially with plugins which cannot be copied, like possible with modules.
Let me try to explain. You can have the same module copied and using different settings - a `Latest News` module instance at one page to show `latest news` category items, another module instance to show `latest announcements` category items. For a plugin you may need to fire it for a category using one set of rules, and for another category - another set of rules. I.e. your plugin adds images to a blog view introtext and you want to use one images size for a `News` category and another size for an `Announcement` category.
The purpose of the library is to simplify developers organizing forms with settings in such cases. Please, have a look at the images below for a example.
Documentation is not ready at the moment, but you can see how backed of this plugin is organized