Lets you specify a new name for a gradient. When you rename a gradient, the renamed gradient will appear in your personal GIMP gradient directory. If, however, you have the permission to alter files in the system-wide GIMP gradient directory, the file will be erased from that directory. This means that other users on the system will not be able to use the gradient even if you only renamed it. So you need to be sure what you are doing. Be fair to others and don't deprive them of gradients!