The LabVIEW Project Provider Framework is a set of advanced APIs that allow you to control and modify the LabVIEW Project window. With it you can do things like add new items to the project window, modify existing items, add extra right-click menu options, add glyphs to the icons, add extra toolbars, etc.
The LabVIEW Project Provider framework is an unsupported feature of LabVIEW. The only documentation for it exists in this community group, and it is community supported only. While NI has no plans to modify or break the existing APIs, there is no guarantee that all features will work in future versions of LabVIEW. Please use at your own risk.