So far i know it creates the 1kb File, when you change the Folder from an Object, what is allready in your scene or an Material thats allready on an Mesh.
The Engine know now where the File moved to.
When you Fix up the Redirected Folders it cleans up everything and finaly the Engine don´t need the 1kb redirect File.
Hope you understand what i try to tell you, my English is not the best