Currently the collaboration cache for BIM360 hosted projects is buried in C:\Users\%username%\AppData\Local\Autodesk\Revit\Autodesk Revit 20xx\CollaborationCache. With more and more being hosted in the cloud it would be a great feature to be able to redirect that CollaborationCache to a custom folder to a secondary harddrive or similar, as primary drives start to fill up very quickly.