A project folder is a folder in the project structure that contains items.
You can do the following with project folders:
Add a new project folder to the project structure and add items to that new folder.
Change the location of a project folder.
Rename a project folder.
Delete an item from the project, provided that the item does not belong to a baseline or release.
Except for renaming a folder, these operations cannot be performed with streams as refactoring changes are made in a work area and not directly to a stream in a repository.